Thanks, ReiRei - as a programmer I know how hard it can be to track down elusive bugs such as this.
I also know that Daniel and the team are fully aware of it and as annoyed by it as we are - and committed to fixing it.
Just that, as you say, it does make some sessions almost impossible to complete.
It seems so random - comes and goes in sequences: two or three hours without it. Then five relaunches in a row!
Maybe the developers have some way of logging the Playhead progress to try and see which other sets of states of variables are present when it occurs; and which not?
I know that switching modes sometimes helps; but in my experience not for long; nor does that guarantee that other runaway instability almost always results… note input clobbered, other screen redraws compromised etc.
If we can help in any way (debugging traces, diagnostics, questions on exact circumstances…), we’re ready! 
Thanks!