Reference now closed thread #255954943. I have a similar issue.
Badge does NOT show up on my iPad, appears only on iPhone.
Have rebooted/restarted phone multiple times. If I turn off badges in notifications, it disappears as expected, but comes back if I enable badges again.
Apple may or may not read postings or bug reports around here.
Log feedback: Product Feedback - Apple
Here is the cited (closed) thread with a similar-looking issue from iOS 18.3:
Home App will not clear notification badg… - Apple Community
You’ll want to mention configuration details such as equipment involved in your feedback, as the cited thread mentions some third-party gear from IKEA. (Or mention it here, and then provide a link here in your feedback to Apple.)
Home App will not clear notification badge after 18.6 update
