ai vector file pdf export with nested indd files

Following setup (all apps at most recent 2026 versions):
indd with linked indd including vector ai files. 

when working cross platform (win and mac), the linked indd file needs to be opened and saved once in order for the vector files to export properly (otherwise they'll just export as white rectangles). once with the other platform again, the indd needs to be saved again for proper pdf export.