At turn 84, black promoted a pawn by moving it to its promotion rank, but it seems chess.com did not reset the 50-move ply count, causing chess.com to report the follow final position FEN:
1b6/8/8/8/8/8/r5k1/2K2q2 w - - 8 88 (chess.com FEN)
If the 50-move ply count was reset on black's 84th turn, the FEN should look like:
1b6/8/8/8/8/8/r5k1/2K2q2 w - - 6 88 (what-I-think-is-correct FEN)
Based on what I understand, the FEN 50-no-progress move count gets reset whenever there is a pawn movement or capture.
I played the following game:
https://www.chess.com/live/game/2133322552
At turn 84, black promoted a pawn by moving it to its promotion rank, but it seems chess.com did not reset the 50-move ply count, causing chess.com to report the follow final position FEN:
1b6/8/8/8/8/8/r5k1/2K2q2 w - - 8 88 (chess.com FEN)
If the 50-move ply count was reset on black's 84th turn, the FEN should look like:
1b6/8/8/8/8/8/r5k1/2K2q2 w - - 6 88 (what-I-think-is-correct FEN)
So, which is correct? and why ?