Hi - The latest update has been causing a major issue with any clip getting scaled down smaller than 51% - it changes the aspect ratio (even though uniform scale is selected) by squeezing it slightly. This incredibly frustrating. Try creating a photo montage or adding multiple Chryons on screen with this behavior. This happens with all kinds of clips - ProRes clips, Sony XDCam, even JPG and PNGs. This is happening both on my Macbook Pro 2019 and my other editors Macbook Pro 2017 (Specs Below)
UPDATE: Weirdly, adding the "crop" effect to the clip fixes the aspect ratio, at least on the output file, not in the program monitor while playing (but is fixed when paused). Note that I haven't changed any crop parameters, or used crop, just simply added the effect to the clip. Its possible other effect would have this, uh, effect, as well.