Longrunning Hangfire Jobs stop exactly after 30 minutes (asp.net core)

I have very long running hangfire jobs, that are supposed to write a live HTTP stream onto a file.
This is all working nice and fine and I can run many jobs at the same time.

However after exactly 30 minutes the Hangfire job terminates and sends a Hangfire.JobAbortedException.
I tried to catch those exception to simply requeue the job, which works fine sometimes and sometimes he considers those jobs as succeeded.

I can’t tell yet, which case occurs under which circumstances.
I’m running a asp.net core 2.0 application that is firing the hangfire jobs.
I have set the application pool settings to start immediately and always running. Idle timeout is 0.

Is there something else I’m missing or any suggestion how I can debug further into this?

One more thing that crossed my mind:
I’m using the Hangfire.MemoryStorage as a storage provider. Does it have a InvisibilityTimeout setting or something that must be set?