ProRes 4444 alpha channel purple fringe in latest versions!
The last two updates to Premiere have introduced a bug where ProRes 4444 material with blended transparency are getting weird jaggy colorful fringes where transparency steps from 0% to 1%. Unfortunately I can't just turn off max depth, because the result introduces banding to those same transparency areas.
I did find a workaround… I added the Ultra Key and set the key color to something extreme that appears nowhere in the graphic, like Green 100% bright. This causes the fringe to disappear. Other effects like Remove Matte also seem to get rid of of by dumbing down the bit depth on just that one layer, but they introduce some undesirable banding in the process.
Chase Smith commented
Manny's solution worked for me! But there doesn't seem to be a way to change the default setting, so I'm doing this for all alphas individually...
Manny Castillo commented
This helped me:
-On the project window (not on the timeline) Right click on the clip with 4444 alpha and select "Modify" > "Interpret Footage".
-In the Alpha Channel section, by default "Use alpha premultiplication from file" is selected. Change it to "Conform Alpha Premultiplication" (no need to select anything else).
Would be nice that it either is selected by default in PR or that it's exported automatically like that from AE. Anybody knows how?
Simon Blervaque commented
I have it too ! Very annoying, please change it as soon as possible