I have a similar problem, happening now the second time in a row in a game against Lord Rat.
I buy the last provinces, end my turn end the game wont end. But its not a freeze, I can still rightclick cards
The log says
t plays a Plunder
t gets 1 VP.
t plays 4 Golds and a Fortune.
t buys and gains a Duchy and 3 Provinces.
after reloading the page, there is also
t shuffles their deck.
t draws a Gold, a Poacher, 2 Hamlets and a Wandering Minstrel.
Reshuffling the Black Market deck.
Waiting for trazoM.
if i try an "/undo 1", I get a neverending "Pending undo request..."