Cannot clear or disable Fill & Sign autocomplete entries

[Yellow2020]

When using the Fill & Sign tool and the text box is selected, the autofill is always on even when Auto-fill is turned off in Preferences.  In addition, there seems to be no way to clear the saved entries.

This has been asked before, but the "solution" assumes you're signed into your adobe account and advises to disable the feature through documentcloud settings.  However, I typically work without signing in, and I can confirm that the autocomplete engages even when I'm not even connected to the internet.  The entries must be stored locally somewhere. 

Is there any way to disable the autofill specifically within Fill & Sign, or to clear it?  As more and more entries get added to this cache, typing in the text boxes seems to get slower and slower as it tries to auto-complete.

Thank you.