I was following the Europe Go Federation League game today locally and was surprised to find that OGS scored the game as W+5.5, when my following of the game gave a score of W+7.5.
The notable thing that happened in this game was that the game had a timeout due to internet lag and then by agreement of the players to resume I believe was resumed using a feature OGS has to fork and resume a game (which I haven’t really used myself, but I presume from the comments this is how the game was resumed). The game and its resumption were here:
If you look carefully, there is a discrepancy in the number of captured stones at the point of timeout and then in the starting position of the next game - white had 2 captured stones, and then in the resumed game OGS failed to remember white’s captured stones and started white as having captured 0. I believe this resulted in OGS erroneously scoring the game as W+5.5, when in reality the score was W+7.5.
Attached is an SGF file I have manually composed together from the two parts if you would like to verify the scoring yourself in the final position. artem92-Avtikh-combined.sgf (3.8 KB)
Thankfully in this case it did not change the winner of the game. However if OGS is going to continue to be a platform for tournaments or professional Go events, I would be concerned if at some point a game resumption like this could take place with the lack of tracking of captured stones affecting the winner of the game without the players or organizers noticing.