Contacts: no importable cards were found

Just leaving this here in case someone hits this annoying snag.

This in MBP 2018 Touch bar running Monterey 12.1

After allowing "Contacts" in iCloud, most of my Contacts vanished. I have to assume iCloud's merging facility took some "intelligent" /s decision and decided to get rid of things... oh well.

Solution:

My contacts were still on a Moto Android so exported the lot, 689 contacts, to a .vcf.

Upon importing the file into to Contacts app, 216 contacts were not imported. I moved the not-imported contacts to separate .vcf and tried to import again and got the dreaded "no importable cards were found" :-( Much tried and test ensued.

It turned out that the first card of the not-imported contacts file had the "NOTE" record split in three lines.

Turning the three lines into a single one by deleting linefeeds (and extra "=" characters), solved the problem and all remaining records were imported.

Hope it helps.