I did a shoot with a Sony A7sIII in 4K. Had to encode 260+ files in a lower resolution to share, so I set up a watch folder in Media enconder. Some files were skipped from the automatic importing. When I tried to manually import them, it said there was a codec incompatibility. Import those files into premiere project and they were imported correctly and playing just right. However, when trying to export them the media would show as Offline.
The only way to solved it was importing them into After Effects and then exporting them from there.