By "Crashing", I mean the game, not my system (which, being 5800X/5700XT/32GB DDR4-3600/PCIE4.0 SSD, is not really 'low-end'); the game engine seems to not "look ahead" enough, and doesn't "pause" when it needs to catch up to the Player, but throws an error and closes.
The initial "Catch Sis Masturbating" freeze appears to be in a similar vein; if you click/Ctrl through the dialog too fast and the cutscene starts before the PC is standing in front of Sis' door, the game will freeze at the point that the PC gets their status change (added lust, etc.) when the cutscene ends.
The errors can be reduced by not using mouse controls at all, and not hitting "Next" until a dialog box completes; somewhat less than fun when you're repeating the same action over 10 days to reach the next level.