Face recognition broken after Lightroom Classic update

[#1]

I've just today opened Lightroom Classic and allowed it to update to 10.0.19041

I'm in the process of tagging years of photos and my first step for each folder is name tagging. I go to People View and tag the faces. It's normally pretty quick.

When I do this now after the update, it just sits at 'Looking for people' indefinitely, even in a folder with only four photos.  If I go back to folders I tagged before the update I can see all the tagging as normal, but all new untagged folders just stick at 'Looking for people'

This is a major part of my reason for using Lightroom so I hope there's a fix.

I'm on Windows 10.