RFXCOM RFXtrx won't add new device

Ive been using this integration for years now for various kinds of sensors. Among them a couple of Cresta wireless Thermo-Hygro sensors. The thing with these is that when you change the batteries it becomes a “new” device. (Luckily you can now easily ‘replace’ your original device with the new one without losing any history.)

I had already ticked the ‘Enable automatic add’ option in the configuration a long time ago, and there were indeed quite a few unknown devices from other people in the neighborhood.

Today I had 2 of these Cresta devices which needed new batteries. When I had changed batteries of the 1st one, I had to browse through the list of unknown devices and after a while I found the right one and then converted the old device to that new one.
Then I decided to first remove all the rest of the unknown devices before changing batteries on the 2nd device. So then I changed the batteries. The device is running again and every once in a while it blinks the LED to indicate it is sending data.

But now the new device just won’t show up as a new ‘unknown’ device.
And this is so very frustrating!

What can I do to fix this?

I have a device that has a simulair behavior when changing the AAA battery.
What i do is connecting the new battery in parallel with the contacts/old battery befire removing the old battery

In the meantime, a couple of hours hours later, several new ‘unknown’ devices from the neighborhood have been added. But my own one still hasn’t. What is this? Is this integration keeping some kind of blacklist?