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Start a new Sandbox game, and perform the following:
Spring 1901: all hold.
Autumn 1901: TRI-ALB, VEN-TRI, all the rest hold.
Instead of performing the one build for Italy, one disband for Austria, instead Move back the Sandbox a turn.
Autumn 1901: TRI-ALB, all the rest hold.
This leads to showing TRI empty but in Italy's color, one disband for Austria, and no builds for Italy!

Interesting! It seems province ownership isn't reset when you move backwards.

Thanks for reporting, will add it to the todo list

I am glad I put off starting the Replay variant playtest. This would have killed the game.