I have a new printer (my second), and most likely have been making mistakes setting up UBL. That said, the "Restore Leveling after G28" plugin failed, letting me know my UBL mesh was broken. That brought up a new question.
I have disabled the plugin, because I assumed it was unnecessary. I have M420 S in my start Gcode, but I guess I could enable it in the firmware instead. Nonetheless, why is this plugin enabled by default? Is it redundant if it is already in gcode or marlin, or is it somehow necessary to have this plugin enabled in Octoprint?
I guess the second question would be, where is the best place to have this command stored, or does it not matter?
Didn't realize I got a response. I don't ever remember installing it. I actually had Octoprint running in venv on a Windows laptop. I made a backup of that and used it for setting up the second printer, which led me to discover it. The second printer, and the first, are now both on Pi's installed with the Pi Imager Octopi option. Both created and tweaked from the backup. The G28 plugin doesn't show up in the settings sidebar, so I never noticed it. Still don't think I installed it , but no matter. I removed it on both.