Inbox coding: advice needed

I am looking for advice about my binding code for auto discovery and Inbox handling.

I have a user who reports getting repeated pairs of Inbox logger messages (see below) which are perpetually repeated every 2 minutes. But on my own test systems I do not see such messages. Therefore I am looking for some suggestions about what could be going wrong for this particular user.

My only hunch is that it might be something to do with the RepresentationProperty; however I am using the same such property both on instantiated Things, and also on non instantiated Things in the Inbox.

2020-11-14 16:45:03.646 [me.event.InboxRemovedEvent] - Discovery Result with UID 'velux:klf200:192_168_1_15' has been removed.
2020-11-14 16:45:21.057 [home.event.InboxAddedEvent] - Discovery Result with UID 'velux:klf200:192_168_1_15' has been added.

For more details fot the problem, see this