Stellaris has started hanging on a particular day in my current game, so I started looking through the error log to see if there was anything obvious going wrong. A few days before the hang, this error shows up:

[13:37:02][trigger_impl.cpp:836]: Script Error: Invalid context switch[owner], file: events/cp_primitive_events.txt line: 9, Scope:

I've no reason to believe that this is causing the hang, but I thought I'd let you know since it probably means that the event isn't working as intended.