RC4 & nightly: editor Autocomplete false is not respected in new session

[cebderby]

I'm consistently seeing the editor autocomplete popups when Autocomplete has been successfully turned off in a previous session and remains off in the preferences.
The entry [editor] enableAutocomplete=false is present in the OpenSCAD.conf, and I've tried hiding the existing config file to get a fresh one, with no difference.
The Preferences panel shows the autocomplete off, number of characters disabled, as expected.
A fix is to toggle the autocomplete on and off (can be done in one visit to Preferences, no need to exit back to the editor in between).
So it seems that reading the =false from the file is failing to turn something off, which toggling off in a session is doing.
Running [Debian-Ubuntu-]Linux Mint MATE 64bit 19.3, OpenSCAD nightly, same in RC4 appimage