If you run into this upon updating your Xperia 5 III to Android 12 this is what I got back from Sony  Support & it does seem to have worked .

Thank you for contacting Sony support.
We are sorry to learn that you are facing issues with your Sony Xperia 5 III after the Android update.
In an attempt to resolve this issue, kindly follow the steps below:
- Go to Settings > Apps & Notifications > See All Apps / App Info > tap on the 3 vertical dots at the top right corner > select Show System > find and tap on ' Xperia Home ' > Storage and Cache > Manage Space > Clear All Data.
Go back one step > tap on Clear Cache > Force Stop.
- Restart the phone and test it.

If the issue remains, please proceed with the steps in the link below:
https://www.sony.co.uk/electronics/support/articles/00237681
If the above steps do not solve the issue, kindly reply with answers to the questions below in order to raise the case for further investigation:
· What is the current Software Version and Android Version installed on the device? Please write the exact version.
· Who is the Network Operator / Mobile Network Provider? (Orange, Vodafone, Proxiumus .. etc.)
· When has the issue started to occur?
· What feature or application were you using when the issue happened?
· What was the latest app you installed recently?
· If you use any third party device please mention it.
· Kindly attach a short video showing the issue.
Should you have any further questions, please feel free to reply to this e-mail.
Thank you for your enquiry.
Yours sincerely,