Masking Subject option unavalaible Lightroom classic 13.1

Ah, in the histogram:

That lighting bolt symbol. Check your process version/

Please post your System Information as Lightroom Classic (LrC) reports it. In LrC click on Help, then System Info, then Copy. Paste that information into a reply. Please present all information from first line down to and including Plug-in Info. Info after Plug-in info can be cut out as that is just so much dead space to us non-Techs and it takes up vast amounts of scroll space making the reply less readable and less likely that others will bother with your post.

Hi Everyone,

I have a problem a random on some of my pics in lightroom.

Masking subject option is unavalaible on some of my picture even if I made a manual face detection of the subject.

The option is grayed out.

Any ideas ?

Lightroom is running on I5 13600K withtout graphic card , 64 Gb drivers are up to date.

Thanks for your help