I am running Quicken Home & Business, upgraded to R50.9 on June 9th. Since then, I am frequently being asked to login to my Quicken account, something that normally happened once every few months. About half the time, I get the "Welcome to Quicken" splash screen - Quicken then goes away for a while before I get access to my data. More annoying is that One-Step Update periodically fails with "your membership has expired". This is not the case - my membership is active until Dec/2024. The only solution is to close Quicken and start again. There are a bunch of posts on this error but they seem to relate to using the Quicken Cloud which I do not.
I found https://community.quicken.com/discussion/comment/20347610 which seems similar but has been closed. I followed the advice but will not know if it actually "solved" until I go a few days without issues.
I have reported the issue twice through Quicken's "Report a problem" but have not heard back.