Photos app not recognizing faces in imported photos on iPhone

I import photos taken with my digital SLR camera to my iphone via Itunes, and have done for many years. These are stored in folders on the phone so I can access them. Previous to IOS18, the phone would identify faces in the imported photos, as well as those taken on the actual phone. I do not use Icloud back up as the photos are all backed up on my PC, and they are transferred using Itunes.

Photos that are imported now do not even recognise that there are faces in them, so I cannot even suggest individuals names.

All versions of Itunes and IOS are up to date, and I have restarted my phone too. Any new ideas welcome - thanks

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