A bit of a long shot, but I wonder if the issue could be tini needing PID 1?
This is just an initial guess based off the error message in your call stack, a cross-reference with our init-snapshot repo, from reading about tini behavior on the actual-server project , and on our platform more generally.
I hope this isn’t a complete misapprehension of what’s going on-- thank you so much for your awesome report 