Often no rain rendered

Often no rain is rendered.  This is sometimes fixed when I run at least one through the 2-hour prognosis—running it again does show rain again.  But sometimes it goes away again.

This happens on the latest F-Droid version (2.1l) on a Samsung Galaxy S10 w/ LineageOS 19.1 (Android 12), as well as with version 2.2 on a Fairphone 4 w/ /e/OS (Android 11).