Amplitube insert not always working (intermittent)

Problem:
I have 4 guitar tracks, all using Amplitube as an insert effect (one on each track).
Sometimes one or more of the tracks stops applying the Amplitube effect even though the Insert is activated.
The problem is intermittent and has only affected a couple of the guitar tracks to date.
I’ve tried de-activating and re-activating the Insert effect but it doesn’t fix it.
I have to restart Cubase or sometimes even the laptop to get Amplitube to work on all the guitar tracks.
As a workaround, I’m thinking I might have to render the tracks when they are working normally.

My set-up:
Cubase Pro 11
Amplitube 3
Windows 10

Thanks for any suggestions

Complete stab in the dark: Do you maybe have some MIDI device that could send control data or program change data to Amplitube and change something in the plugin?
It could also be some weird bug in the plugin. Do you have the latest available version installed?

If the situation happens: did you really disable the plugin (ALT+click) or just bypass it?
What about if you reload the whole plugin and then load the preset again (requires saving the working state as a preset beforehand, of course)?

Thanks for the advice. I’ll try these ideas to see if I can isolate what’s happening.
Cheers