I realized that the game stops you from attacking enemy units at the turn they surrender, so I tried to target the enemy city with nuke at the turn they surrender before any treaty was signed, and wanna see a nuke launched to a city that is not in war with me. I could still do the targeting, but the game froze and can not load to the next turn.  I guess the game should not alllow you targeting enemy city when they send the surrounding treaty.

here is what appeared when i tried to reload that turn 

The operation was canceled.

  at Amplitude.Mercury.Game.Game+<DoStart>d__4.MoveNext () [0x00157] in <e606c76f24df4f658f27082af4ec6286>:0 

  at Amplitude.Coroutine.Run () [0x00019] in <a38bac599c844a99a8a4fcca3b37292e>:0 

here is the fileDiagnostics (2021'08'20 @0347'31''953''').html