While making the 15 GL transitions video, came across a bug affecting the mask simple shape filter.
When I exported the video using the default export profile with parallel processing, the bow tie vertical and bow tie horizontal transitions were jittery. Re exported the video with parallel processing off. The result is no jitters.
Two clips, one with Parallel processing on and the other with it off are in a zip file here. https://drive.google.com/open?id=14I6G72BtqX77ztVROuJ96u4WMPlzOEVn
The presets to produce the effects are here.
Bow Tie.zip (973 Bytes)