Harper undoes itself on Fandom

**Describe the bug**
Harper undoes all it's grammar fixes on fandom editing, when i move to another sentence, it undoes all the fixes i do

**To Reproduce**
Steps to reproduce the behavior:
1. Go to any fandom site to try and edit
2. Click on fix grammatical errors
3. go to next sentence
4. UNDOES ITSELF

**Expected behavior**
I expected that no other change would occur, that it would stay the same, so it could be fixed and i wouldn't meticulously try to fix it!

**Platform**
Firefox, MacOS

Start by reproducing the issue on a Fandom editing page in Firefox on macOS: apply grammar fixes, move to another sentence, and observe whether the changes are undone. Trace the editing flow responsible for applying fixes; done means fixes remain in place when moving between sentences.

Written by the indexing model from the issue text.