Match Loss despite opponent disconnection for 20 minutes.

As above. Opponent disconnected for 20 minutes, reconnected in the final seconds and then match ended. Opponent did not swing to win and take final prize cards however the game determined that final prize cards were taken.

Is this a common bug or an exploit?

Game Log below.

Setup
SugaredCriminal chose tails for the opening coin flip.
Javbk201 won the coin toss.
Javbk201 decided to go first.
SugaredCriminal drew 7 cards for the opening hand.

• 7 drawn cards.
  • Nest Ball, Superior Energy Retrieval, Earthen Vessel, Gholdengo ex, Buddy-Buddy Poffin, Hisuian Heavy Ball, Basic Water Energy
  Javbk201 drew 7 cards for the opening hand.
• 7 drawn cards.
  SugaredCriminal took a mulligan.
• Cards revealed from Mulligan 1
  • Nest Ball, Superior Energy Retrieval, Earthen Vessel, Gholdengo ex, Buddy-Buddy Poffin, Hisuian Heavy Ball, Basic Water Energy
  Javbk201 drew 1 more card because SugaredCriminal took at least 1 mulligan.
• Javbk201 drew a card.
  SugaredCriminal played Bidoof to the Active Spot.
  Javbk201 played Dreepy to the Active Spot.

Turn # 1 - Javbk201's Turn
Javbk201 drew a card.
Javbk201 played Artazon to the Stadium spot.
Javbk201 attached Basic Fire Energy to Dreepy in the Active Spot.
Javbk201 played Ultra Ball.

• Javbk201 discarded 2 cards.
  • Iono, Xatu
• Javbk201 drew Dragapult ex.
• Javbk201 shuffled their deck.
  Javbk201 played Artazon.
• Javbk201 drew Tatsugiri and played it to the Bench.
• Javbk201 shuffled their deck.
  Javbk201 ended their turn.

Turn # 1 - SugaredCriminal's Turn
SugaredCriminal drew Canceling Cologne.
SugaredCriminal played Artazon.

• SugaredCriminal drew Gimmighoul and played it to the Bench.
• SugaredCriminal shuffled their deck.
  SugaredCriminal played Earthen Vessel.
• SugaredCriminal discarded Canceling Cologne.
• SugaredCriminal drew 2 cards.
  • Basic Metal Energy, Basic Water Energy
• SugaredCriminal shuffled their deck.
  SugaredCriminal attached Basic Metal Energy to Gimmighoul on the Bench.
  SugaredCriminal played Prime Catcher.
• Javbk201's Tatsugiri was switched with Javbk201's Dreepy to become the Active Pokémon.
• SugaredCriminal's Gimmighoul was switched with SugaredCriminal's Bidoof to become the Active Pokémon.
  Javbk201's Tatsugiri is now in the Active Spot.
  SugaredCriminal's Gimmighoul is now in the Active Spot.
  SugaredCriminal's Gimmighoul used Call for Family.
• SugaredCriminal drew Origin Forme Palkia V and played it to the Bench.
• SugaredCriminal shuffled their deck.

Turn # 2 - Javbk201's Turn
Javbk201 drew a card.
Javbk201's Tatsugiri used Attract Customers.

• Javbk201 shuffled their deck.
  Javbk201 evolved Dreepy to Drakloak on the Bench.
  Javbk201's Drakloak used Recon Directive.
• Javbk201 drew a card.
  Javbk201 attached Basic Psychic Energy to Drakloak on the Bench.
  Javbk201 ended their turn.

Turn # 2 - SugaredCriminal's Turn
SugaredCriminal drew Nest Ball.
SugaredCriminal played Artazon.

• SugaredCriminal drew Gimmighoul and played it to the Bench.
• SugaredCriminal shuffled their deck.
  SugaredCriminal played Nest Ball.
• SugaredCriminal drew Radiant Greninja and played it to the Bench.
• SugaredCriminal shuffled their deck.
  SugaredCriminal's Radiant Greninja used Concealed Cards.
• SugaredCriminal discarded Basic Water Energy.
• SugaredCriminal drew 2 cards.
  • Buddy-Buddy Poffin, Basic Water Energy
  SugaredCriminal played Buddy-Buddy Poffin.
• SugaredCriminal drew Gimmighoul and played it to the Bench.
• SugaredCriminal shuffled their deck.
  SugaredCriminal attached Basic Water Energy to Radiant Greninja on the Bench.
  SugaredCriminal ended their turn.

Turn # 3 - Javbk201's Turn
Javbk201 drew a card.
Javbk201 evolved Drakloak to Dragapult ex on the Bench.
Javbk201 played Switch.

• Javbk201's Dragapult ex was switched with Javbk201's Tatsugiri to become the Active Pokémon.
  Javbk201's Dragapult ex is now in the Active Spot.
  Javbk201 played Artazon.
• Javbk201 drew Dreepy and played it to the Bench.
• Javbk201 shuffled their deck.
  Javbk201's Dragapult ex used Phantom Dive on SugaredCriminal’s Gimmighoul for 200 damage.
• Javbk201 put 5 damage counters on SugaredCriminal's Gimmighoul.
• Javbk201 put a damage counter on SugaredCriminal's Gimmighoul.
  SugaredCriminal's Gimmighoul was Knocked Out!
  Basic Metal Energy was discarded from SugaredCriminal's Gimmighoul.
  SugaredCriminal's Gimmighoul was Knocked Out!
  SugaredCriminal's Gimmighoul is now in the Active Spot.
  Javbk201 took 2 Prize cards.
  A card was added to Javbk201's hand.
  A card was added to Javbk201's hand.

Turn # 3 - SugaredCriminal's Turn
SugaredCriminal drew Energy Retrieval.
SugaredCriminal's Radiant Greninja used Concealed Cards.

• SugaredCriminal discarded Basic Water Energy.
• SugaredCriminal drew 2 cards.
  • Gholdengo ex, Gholdengo ex
  SugaredCriminal evolved Gimmighoul to Gholdengo ex in the Active Spot.
  SugaredCriminal's Gholdengo ex used Coin Bonus.
• SugaredCriminal drew Hisuian Heavy Ball.
• SugaredCriminal drew Basic Water Energy.
  SugaredCriminal played Energy Retrieval.
• SugaredCriminal moved SugaredCriminal's Basic Metal Energy to their hand.
• SugaredCriminal moved SugaredCriminal's Basic Water Energy to their hand.
  SugaredCriminal played Hisuian Heavy Ball.
• SugaredCriminal moved SugaredCriminal's Gimmighoul to their hand.
• SugaredCriminal moved SugaredCriminal's Hisuian Heavy Ball to the Prize cards.
• SugaredCriminal shuffled their Prize cards.
  SugaredCriminal played Gimmighoul to the Bench.
  SugaredCriminal played Artazon.
• SugaredCriminal shuffled their deck.
  SugaredCriminal attached Basic Metal Energy to Gholdengo ex in the Active Spot.
  SugaredCriminal's Gholdengo ex used Make It Rain on Javbk201’s Dragapult ex for 100 damage.
• SugaredCriminal discarded 2 cards.
  • Basic Water Energy, Basic Water Energy

Turn # 4 - Javbk201's Turn
Javbk201 drew a card.
Javbk201 played Earthen Vessel.

• Javbk201 discarded Technical Machine: Devolution.
• Javbk201 drew 2 cards.
  • Basic Fire Energy, Basic Psychic Energy
• Javbk201 shuffled their deck.
  Javbk201 attached Basic Fire Energy to Dreepy on the Bench.
  Javbk201 played Artazon.
• Javbk201 drew Natu and played it to the Bench.
• Javbk201 shuffled their deck.
  Javbk201 played Boss's Orders.
• SugaredCriminal's Radiant Greninja was switched with SugaredCriminal's Gholdengo ex to become the Active Pokémon.
  SugaredCriminal's Radiant Greninja is now in the Active Spot.
  Javbk201's Dragapult ex used Phantom Dive on SugaredCriminal’s Radiant Greninja for 200 damage.
• Javbk201 put 5 damage counters on SugaredCriminal's Gimmighoul.
• Javbk201 put a damage counter on SugaredCriminal's Gholdengo ex.
  SugaredCriminal's Radiant Greninja was Knocked Out!
  Basic Water Energy was discarded from SugaredCriminal's Radiant Greninja.
  SugaredCriminal's Gimmighoul was Knocked Out!
  SugaredCriminal's Gholdengo ex is now in the Active Spot.
  Javbk201 took 2 Prize cards.
  A card was added to Javbk201's hand.
  A card was added to Javbk201's hand.

Turn # 4 - SugaredCriminal's Turn
SugaredCriminal drew Boss's Orders.
SugaredCriminal's Gholdengo ex used Coin Bonus.

• SugaredCriminal drew Earthen Vessel.
• SugaredCriminal drew Basic Water Energy.
  SugaredCriminal played Earthen Vessel.
• SugaredCriminal discarded Lost Vacuum.
• SugaredCriminal drew 2 cards.
  • Basic Metal Energy, Basic Water Energy
• SugaredCriminal shuffled their deck.
  SugaredCriminal's Gholdengo ex used Make It Rain on Javbk201’s Dragapult ex for 150 damage.
• SugaredCriminal discarded 3 cards.
  • Basic Metal Energy, Basic Water Energy, Basic Water Energy

Turn # 5 - Javbk201's Turn
Javbk201 drew a card.
Javbk201 played Arven.

• Javbk201 drew 2 cards.
  • Rare Candy, Rescue Board
• Javbk201 shuffled their deck.
  Javbk201 attached Basic Psychic Energy to Dreepy on the Bench.
  Javbk201 evolved Natu to Xatu on the Bench.
  Javbk201 lost connection and reconnected to the server.