I tried a game of Imposter Chess using the 'Move' feature and generated
the following move list:
1. P d2-e4
1... p e7-e5
2. N g1-f3
2... n b8-c6
3. N f3-e5;p-C1
3... n c6-e5;N-B8
It seems to work ok. I also tried Takeover Chess 'solitaire' and its
worked ok too.
I would suggest trying the game again to see if the errors recur.