In game #5637757 on frankfurt on my turn 21 i bought the last colony and hit "end turn" to end my turn and the game. After hitting the button it disappeared but the game did not end. I was still able to chat with the other player who had the same issue.
I then requested an undo and he could see that, but i cancelled it and when trying to request it again to repeat the last colony buy the undo request did not work anymore.
My opponent then tried to resign but i dont know if that worked for them. For me it didnt, I'm still in the game but they disconnected/reconnected and then left the table. I want to try kicking them via the idle timer but i dont know if it will show up, so far it hasn't.
I also noticed after some page reloads that i had still 2 buys (and $0) left and the little "+" sign on copper indicated i could buy them. I tried that and the game froze, but after reloading i had only 1 buy left and the log showed me having bought a copper. I repeated that for another copper, dropping me down to 0 buys but that also didn't end the game, it just showed a new hand when i reloaded after the second copper freeze (presumably the one i wouldve been dealt next turn)
I went off to do something else and stayed logged in in that game for about 45 minutes. When I came back, it didn't show the "make opponent resign" dialog but instead after reloading the page my opponents name had changed to "UNKNOWN_2410". I tried resigning but that didn't get me out of the game either. In the end i kicked myself from the login screen via "kick and resign" and that worked.