RotomV Ability Bugged

Positive.

They used it once earlier in the game and it worked properly. Their turn continued after the second use.

Also, that's kind of how bugs work. That is to say, they happen sometimes for some people, but not others. Perfect example, Instant Charge working properly the first time in the game in question but behaving irregularly the second time in the same game no less.

Or it could have been cheating. Opponent would have lost if not for being able to continue after the second Instant Charge. But to err in favor of giving benefit of the doubt, let's call it a bug.

Guess we'll have to agree to disagree. Everyone on the Internet is a master coder, afterall.

First, its improper to assume people only ever use Instant Charge on their first turn of the game. In fact, my opponent used Instant Charge on their second turn in the game in question (there were dead draws on both sides).

Second, "[e]ither they work as they should or they don't depending on the situation" is not only inconsistent with your saying this behavior "wouldn't be intermittent," it is directly opposed to your saying "[c]ard functions have always been consistent" in the previous sentence. Further, it is exactly my point -- bugs aren't consistent across all players at all times.

Third, your presenting anecdotal evidence as to the behavior of Abilities in general and then seeking anecdotal evidence from me about Abilities in general is irrelevant (a) because we're talking about Instant Charge specifically, and (b) because it has nothing to do with the nuts and bolts behind Instant Charge, or any Ability for that matter. Your past experience with Instant Charge or any other Abilities, my past experience with Instant Charge or any other Abilities, or the experience of anyone else with Instant Charge or any other Abilities has no bearing on what happened in that particular time, under that particular server load, etc.

Finally, the only condition on Instant Charge is if you use the Ability, your turn ends. There's no "once per Rotom per turn", "can only use one Instant Charge per turn," "can only use Instant Charge on your first turn of the game", or anything else attached. Therefore, the only way this could be coded for Instant Charge to work properly in the first place is "if use Instant Charge, then Turn Ends." And again, my opponent used Instant Charge for the first time on their second turn of the game, so that puts an end to what seems to be your theory of Instant Charge being improperly conditioned to only work only on the user's first turn.

This was supposed to be a simple Bug Report. Not a trouble shooting/coding theory session with a random person who isn't on the dev team.