Due to bugs introduced in the recent versions of Final Cut Pro (10.4.9 or newer, including 10.5) and Apple Motion (5.4.6 or newer, including 5.5), the following actions may corrupt our plugins' registration in macOS:
Sending to Compressor (either from Final Cut Pro or Motion),
Exporting MP4 from Motion,
Saving Motion projects with the "Save preview movie" option enabled.
To fix the issue, please reinstall affected plugins using mInstaller or manual PKG installers that can be downloaded from your 'My Products' page (the download link will appear once you hover your cursor over the preview miniature): https://www.motionvfx.com/user/products
After you've done that, try to avoid aforementioned actions or the issue will reappear.
Note that we don't officially support Compressor as we've received many problem reports and some of them resurfaced with recent FCPX/Motion updates – therefore, we suggest exporting directly from FCP or Motion. If you need to use Compressor, there's a workaround for FCP (not for Motion, though): open the File > Share > Add Destination dialog and add a Compressor Settings destination. After that, export your projects by selecting the newly added destination in the Share menu instead of using the Send to Compressor command.
If you depend on Compressor, be sure to report this bug to Apple via their feedback page: