See this video for what I mean:
https://imgur.com/vV2ZaCe
Here's another video of me creating a new MIDI item and recreating the bug:
https://imgur.com/C6BeCvB
When stretching a selection of MIDI notes, sometimes the notes will not stretch properly when trying to stretch them narrower than a certain width (which is also random).
When trying to stretch the notes wider, it usually works as expected (albeit snapping to non-existant grid lines).
When trying to stretch the notes narrower, it completely disregards the grid lines and converges at a single random point.
This occurs randomly and sometimes occurs immediately or after some undos.
I am using Reaper 6.57 on Windows. However this issue has been present in most older Reaper versions as well.