[PyQt] Crashing on OSX

I’ve been hitting into weird python crash lately when using PyQt on OSX.

I can’t pinpoint error to exact line, because crash happens after my function which is triggered by signal ends. It also doesn’t happen always, in 3% of cases everything works, other times crash.

Functions destroys UI QGridLayout, creates another and reparents it. Adds few new buttons and starts multiple threads for gathering thumbnails from server using ExifTool. I use same code for thumbnailing in two places, one place works always, this second one crashes almost all the time.

Tool works perfectly on Windows platform, this error occurs only on OSX and it looks like system crash titled:
Python quit unexpectedly while using QtGui plug-in.

Here is error I’m getting: PyQt Crash - Pastebin.com

Could anyone help me point in right direction, because I’m having hard time understanding this error message.