Same here!
I have been facing this since yesterday on web WhatsApp on Microsoft Edge. Messages in the web app stop syncing with mobile after a while of usage, and on refreshing the page, I am asked to scan and login each time. Happening several times a day and even when I'm continuously using my office desktop. No 'keep me signed in' option is displayed on the QR code scanning page. After each scan, it is counted against my limit for the maximum number of linked devices allowed. Then I have to manually log out of my previously logged sessions in my mobile app.
Never faced this before, and I have been using this regularly since the feature was launched. I hadn't changed anything on my desktop since Dec 30th, 2022, when I used it last before the weekend break. Maybe a 2023 problem???
Note: My WhatsApp app, which I have been using for my alternate WhatsApp number and installed on the same system, is working fine, though.