DeltaMikeCharlie - with the my change i can dump the mux
holli@satip:~$ time curl -m 120 -u holli "http://localhost:9981/stream/mux/7b8d0f8fe3bd21eeb20f30f1241ef5bb" > muxdump1127325.ts
Enter host password for user 'holli':
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 591M 0 591M 0 0 5049k 0 --:--:-- 0:02:00 --:--:-- 5027k
curl: (28) Operation timed out after 120000 milliseconds with 620453580 bytes received
real 2m4.701s
user 0m0.149s
sys 0m0.872s
you can download the file if needed from here [https://cloud.holli.at/s/jj5nZQzxt7MDz86]
it would be strange if this is a hardware issue that only this single mux is effected and as mentioned before it looks like all service are found and playable - and yes - it makes no difference if tvh takes the adapter directly or it uses it from minisatip - here is an abort (mux dump) tvh using the tuner itself [https://cloud.holli.at/s/WFGzTS2oY56ZZ9M]
@Flole if I remove my code change - tvh is still crashing
these are the service found on that mux - with my code change and playable - which one is missing compared to your env. 
