gpx.ini gets set to all "None" values

[jamagin]

Octoprint 1.3.9, GPX plugin 2.6.2
Printer: Qidi Tech I (dual-extruder makerbot replicator clone)

Since recent upgrades (I left the printer idle for 2-3 months then started using it again in the past couple weeks -- let me know if there's an easy way to piece together upgrade history from logs), the gpx.ini file seems to frequently get reset to a bunch of None values (and others that seem like defaults). This causes the printer to not even have the correct axes or number of extruders. The only solution seems to be to go to the GPX plugin settings page, hit save, and restart the octoprint server. I've attached the 'broken' and 'correct' (i.e. after the workaround) ini files.

gpx.ini.broken.txt
gpx.ini.correct.txt

[jamagin]

I think this is some kind of UI bug.
If i open the configuration UI (wrench icon) and click save in a non-GPX tab, some of the time I get the broken gpx.ini
If I open the configuration UI, go to the GPX tab, and click save, I get the correct gpx.ini.

(Firefox 62.0.2 on windows 10, uBlock origin and uMatrix -- though I don't think those are blocking anything relevant)