Drumgizmo + ardour = delay after some time

Getting Stuff Done How do I .... ?
#1

I use drumgizmo with ardour and after some time (usually after some jack applications being started and stopped) the drumgizmo playback by ardour is audibly delayed. Other inputs are not affected.

I’m pretty sure that it’s an ardour issue as restarting ardour (without restarting any other applications) fixes it.

The drumgizmo timing humanizer is disabled as it’s known to cause delays.

Does anyone have an idea how to debug the issue?
Is there possibly some ardour latency algorithm going havoc?

My full audio chain is:
USB MIDI device → various MIDI programs (ALSA) → a2jmidid → drumgizmo (not the lv2 plugin, but the command-line variant; jack2) → ardour (jack2) → USB sound interface (different from the USB MIDI device)

#2

I switched to the drumgizmo LV2 plugin instead of the standalone version and so far the issue seems gone…

I still don’t understand why the LV2 plugin has stereo outputs for each mono sample (the standalone version doesn’t have that issue), but oh well…

#3

I believe i remember having the same issue with the VST version of drumgizmo…

#4

The timing humanizer is known to cause delay as well, i.e. you may have forgotten to disable it.