mainstage metronome stops unexpectedly

I can't wrap my head around this. My metronome sometimes stops unexpectedly. The playback continues though.

So to make it visual: I start the metronome by pressing the spacebar, green play and purple metronome are on, but then suddenly the purple metronome light goes off, the play stays on. And so the click stops. I don't have any issues with playback as such.

I have used several different midi routings, where the common denominator is an X-air18 used as interface.

But when looking at my midi monitor, it doesn't seem to send any suspicious midi signals which would stop the metronome.

Can anybody help me with this problem? Because the only workaround now is to have logic bounce a metronome track and use playback to play it in mainstage. That's rather annoying...