I think it was on the Redux version of RC5, but more strangely, I can't seem to reproduce this bug.
The "Exception" file had been updated to reflect the bugs. Here are the last two instances, hidden in spoiler tags. Maybe it's a case of after the Exception appears, the game then starts working properly?
Exception raised at 12/11/2020
Happened in: TGameWindow.DoDraw
Class: EBackend
Message: Can't allocate the DIB handle
fRenderInterface: Valid
fRenderInterface.LemmingList.Count: 2
fRenderInterface.SelectedLemming: nil
fRenderInterface.HighlitLemming: nil
fRenderInterface.ReplayLemming: nil
fRenderInterface.SelectedSkill: Digger
Exception raised at 12/11/2020
Happened in: TGameWindow.DoDraw
Class: EBackend
Message: Can't allocate the DIB handle
fRenderInterface: Valid
fRenderInterface.LemmingList.Count: 3
fRenderInterface.SelectedLemming: nil
fRenderInterface.HighlitLemming: nil
fRenderInterface.ReplayLemming: nil
fRenderInterface.SelectedSkill: Digger