Same problem here. Roughly around once a week the app "loses" the login, and/or the premium widgets lose connection and show a "login to Windy" sticker. Got worse in the recent months (or maybe I get more aware of/sensitive to the odd behaviour).
The presets mostly return when logging back in (occasionally it loses the 1/3hr setting, and the initial weather radar reverts to the wind screen), but no other apps require these continued re-logins.
Both on iphone and IPad, version ios/IPadOS 17.2. The app has allreq'd permissions.