Lightroom 7.2: Won't import .mov files from Canon 5DMkII

Hadn't done video for a while with my 5DMkII so was surprised when my import from my memory card hung. Did usual reboot/restart that LR loves, and still had the same behaviour, and also with my next memory card with .mov files.

I had been paying more attention to the random changes on the destination sidepanel (it was switching between showing no / some / all target folders, sometimes in a mini slideshow-like sequence, other times when trying to select/deselect files from an earlier shoot that were already imported, so the non-importing of the .mov files wasn't obvious to me at first.

I copied the .mov files from both all cards into a folder on my hard drive, and although - as before - it showed the thumbnails for the .mov files, they were never imported (LR hung with nothing imported).