Some Bugs, Linux mint 20.

Hi @skarpo44, thanks for the report (and as @TAERSH already mentioned, you should update and use the latest v0.9.18). thanks again

however

1. Helm LV2 Instrument parameters get mucked with after re opening a qtractor session...
Yes, I've seen this very strange behavior with Helm-LV2 before and quite frankly it seems to be the only one LV2 instrument plugin having this trouble on qtractor; moreover it seems to happen on some Helm presets but not others, very puzzling indeed...

2. Splitting tracks does nothing...
Splitting is for clips, not tracks, maybe that's the confusion? and to add to that there are two different ways of splitting clips:
a. Edit > Split: targets current selected clips and splits clips on selection boundaries; disabled if there are no current clip selection.
b. Clip > Split: applies only to current highlighted clip and splits the clip on the play-head location; disabled if there is no current highlighted clip and the play-head is not currently located over it.
please make sure you observe the rules for each case (from the video I think you're failing with case a. where you have no clip selected).

3. Helm closes after clicking MIDI learn in it...
Could not reproduce this at this time--it's not that clear what really happens in your video but I seem to have an different (older?) version to Helm-LV2 here as it seems to not show a 3rd-option on the right-click/context-menu ("Clear MIDI Assignment") while clicking on the 2nd-option ("Learn MIDI Assignment") does nothing...

the Helm-LV2 issues are really weird though I'll try to build a new version (v0.9.0) and look around ... someday :)

[Edit:] Found the culprit for 1. Helm LV2 Instrument parameters get mucked...: when changing presets from the GUI, and only from the GUI, all the internal host parameter values (ie. LV2 control input ports) don't get reset to the new state, probably remaining with any of the previous values, which are saved as if no change of preset had occurred. To workaround this problem you better off only loading presets from the generic plugin > Properties... dialog; OR use Helm-VST plugin, where this problem is non-existent.
byee