Apple Watch storage issue

My Apple Watch 4 suddenly started eating up storage at the rate of 400 to 500 MB a day. At the end of last month the Watch sent me out-of-storage notifications every couple of hours. A first for me. I use the watch for for workouts, notifications (messages and one email account) and timekeeping. No photos, music, podcasts, or 3rd party apps. I have only three watch faces installed.

After resetting the Watch, I regained all but about 3 GB of storage, which I think is normal. But the Watch resumed adding 400 to 500 MB a day. I called Apple Support twice and eventually was bumped up to an expert technician. She was very helpful, put me on hold while she talked to the engineers who are working on the issue. Turns out others have had this problem which is not related to any particular model Watch or OS version. She asked me a list of questions, downloaded settings screenshots and logs from my watch. Finally she had me set it up as a new watch – the behavior hasn’t changed. On the 14th I installed the update to WatchOS. Again I regained all but 3 GB of storage but the behavior hasn’t changed.

Has anybody here had storage issues? Can anyone suggest a fix?