error encountered while discovering extension

ALL,

This is probably off-topic, but I'd like to ask you this since I have no idea where to start...

I am developing an application which involves thread.

Everything compiles and runs fine, however upon exiting (on OSX) I'm getting following message in Terminal from running in lldb:

2020-07-21 13:46:54.262924-0500 dbhandler[56213:723869] errors encountered while discovering extensions: Error Domain=PlugInKit Code=13 "query cancelled" UserInfo={NSLocalizedDescription=query cancelled}
Process 56213 exited with status = 0 (0x00000000) 

Like I said in the beginning, there is no useful information here. It looks like the process finished successfully (status = 0). And when I just do:

open dbhandler.app

follow the same route and then exit the application, I see a busy cursor for a second and the application just shuts down. No crash report.

I suspect that the thread is still executing at the time the shutdown occurs.

So my question is - how can I confirm or deny my thread suspicion?

TIA!