Force Premiere to use XMP sidecar files
Entering file metadata on multiple clips at once seems to cause Premiere to crash for some of us. (See this issue reported almost a year ago: https://adobe-video.uservoice.com/forums/911233-premiere-pro/suggestions/36933751-bug-entering-xmp-metadata-in-batches-causes-crash)
It seems that one way to resolve this issue might be to create a setting that forces Premiere Pro to write XMP metadata to sidecar files even if a given file format supports embedding it within the file.
Even if this issue were to be fixed, it seems like sidecar files would be less error prone and I personally would feel more at ease if Premiere wasn't altering my video files in any way, even if just for metadata.
Premiere Pro uses .xmp sidecar files for MXF files, and some MPEG-1 formats. We will continue to embed the XMP data in the formats which support it.
We’d rather fix the crashes you reference, than change how metadata is handled for numerous file formats.