Apple has updated both iMovie and Final Cut Pro X with a minor fix that addresses a bug in both video editing apps.
According to Apple's release notes, the updates address an issue that caused video frames to be out of order during export or playback. That bug fix was the only listed addition in Apple's release notes.
Some Final Cut Pro X users has noted that the bug specifically affected ProRes workflows. Prior to the update, only inconvenient workarounds like optimizing media files worked.
Apple's last update to iMovie and Final Cut Pro was released earlier in 2022 and also addressed several bugs.