in TSF, the Potion of Giant Strength has a permanent effect, which can be resolved by deleting the character's corresponding EFX files.
Which I did for a savegame in Pools, for the whole party. Which then caused the RoEI to reliably break, with all the need to re-ready it between combats, and failing to DISPLAY after combat. Also, the permanent Protection from Evil for Paladins was gone and didn't come back; tried resting, transitioning areas, even REMOVE, SAVE, QUIT, LOAD and re-ADD to party. Couldn't find a trigger to have the game re-evaluate the spell effects stuff on characters.