Some of the transitions slightly reduce the resolution of the footage while animating. This issue might be apparent when working with stills, sharp images or upscaled footage.
1. Make the transition quicker by shortening the clips
By shortening the clips you're speeding up the transition, which should make the quality transition less apparent. Here is how:
2. Make sure to view your sequence at "Full Resolution"
Sometimes when working in 1/2 or 1/4 the issue is only visible during the preview and not so much in the final render. Make sure to preview the transitions on 100% resolution 1:1 before judging the quality.
Explanation why this happens.
This is due to limitations of native effects in Premiere. We're using only native Premiere effects because this way Premiere Composer is not needed to render your sequences (you can share the project or open it at later date without worrying about Premiere Composer).
What is your use case?
Is this happening a lot to you? Please, let us know.
We're always working on updates, trying to find ways to fix this.