Fatal Python error: GC object already tracked I have a script that updates a text object, using a frame_change_post handler. The scene is imported as a strip in the VSE (for subtitling). It works fine but when I render the animation, it crashes after an inconstant amount of frames.

Append frame 57 Time: 00:00.37 (Saving: 00:00.11)

Append frame 58 Time: 00:00.38 (Saving: 00:00.12)

Append frame 59 Time: 00:00.40 (Saving: 00:00.12)

Fatal Python error: GC object already tracked

Current thread 0x00007f80aeccf800 (most recent call first):
File "/usr/share/blender/2.74/scripts/modules/addon_utils.py", line 200 in &lt;lambda&gt;
File "/usr/share/blender/2.74/scripts/modules/addon_utils.py", line 199 in modules
File "/usr/share/blender/2.74/scripts/startup/bl_ui/__init__.py", line 111 in addon_filter_items
File "/usr/share/blender/2.74/scripts/startup/bl_ui/space_userpref.py", line 1237 in draw
Aborted


Looks like I am doing something wrong... here's the code and, in case it's relevant, the script in action
OK, I solved the crash situation changing the handler from :

frame_change_post


to

frame_change_pre


Which makes sense...