In the current version of the game on itch.io.
I found a bug where after completing the Maid/Pony ending, it's impossible to obtain the acid to dissolve the Maid/Pony outfit. For some reason, the conversation with Jean only offers an option where your character cannot speak. The only fix that works for me involves:
1. Turn off the game.
2. Create a temporary folder outside of the game folder.
3. In the game folder tboe_0021c_win > tboe_mods > base > items, find all files starting with "pony" or "maid" and move them to the temporary folder.
4. After launching the game, these items should disappear because they no longer exist in the game files.
5. Turn off the game again and move the files back into the items folder.
6. After restoring the files and launching the game, you can continue playing. The Maid/Pony ending remains completed, which you can verify on the TV in the room where Jean sits.