I've been editing some older Premiere projects that were built using Windows. A few of the things I noticed are,
- Premiere reports the Gotham font is missing even though it is installed on the Mac. The workaround is to put text on the timeline using the Gotham font and then delete it. This would make the warning go away when exporting. I would imagine this could happen with any non-system font.
- When rendering a project with captions, captions will be burned into the video, regardless if you select Sidecar in the export settings.
I do not know what version the Windows projects were created in.