Safari keeps forgetting passwords, until app restarts
As the title says, Safari keeps forgetting my passwords - nothing autofills and when I look in the Passwords in Settings it is completely empty. Happens every week now and seems to be getting more frequent - it's been happening for a few months, but it's getting more annoying! Quitting Safari and reopening always fixes it (so far!). Today it forgot all the passwords except the compromised / repeated ones (well I know those already don't I as they're all the same!), but all the passwords were there again when I closed Safari and restarted.
Latest MacOS and Safari on iMac 2020 27". Passwords seem work on my old (far less used) iMac and always work on my iPhone, just the daily iMac. No extensions installed.
I assume it is some config file that has corrupted, but where is it?
iMac 27″, 13.4