Item not visible in Paper UI or HABPanel, but REST API shows right value

Hi, I have a weird behavior with the NIBE heatpump binding (the one gathering data over UDP): There is one item which doesn’t show up in Paper UI --> Control, nor in HABPanel (here it stays empty, not even name or NaN are shown). However, if I use the REST API the item is there and shows the right value, e.g. if I run http://openhab.local:8080/rest/items/NibeSupplyPumpSpd. Any idea what this could be??

My item definition for the item is:
Number NibeSupplyPumpSpd “Supply pump speed” {channel=“nibeheatpump:f1x55-udp:myNibe:sensor#43437”}

Does this Item appear in the Items menu in PaperUI?

If you search through /var/lib/openahb2/jsondb/org.eclipse.smarthome.core.thing.link.ItemChannelLink.json does that Item appear anywhere?

Does it appear in org.eclipse.smarthome.core.items.Item.json?

Hi, yes, it does appear under Items and it is also linked to the Channel of the Nibe Thing in PaperUI. Configuration is done with config files and PaperUI automatically reflects that in the GUI. ItemChannelLink.json only contains

{}

and Item.json does not exist (as I only configured items in config files). Funny thing: The item does appear in the events.log and alternates between 1 and 70 in short intervals. 70 is the maximum value allowed for the pump, so I guess the data gets through.

2020-04-21 08:59:44.293 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 1 to 70
2020-04-21 09:00:12.174 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 70 to 1
2020-04-21 09:00:18.282 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 1 to 70
2020-04-21 09:06:05.078 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 70 to 1
2020-04-21 09:06:16.189 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 1 to 70
2020-04-21 09:06:37.071 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 70 to 1
2020-04-21 09:06:50.179 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 1 to 70
2020-04-21 09:07:09.066 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 70 to 1
2020-04-21 09:07:22.187 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 1 to 70
2020-04-21 09:07:41.054 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 70 to 1
2020-04-21 09:07:57.166 [vent.ItemStateChangedEvent] - NibeSupplyPumpSpd changed from 1 to 70

But its impossible that the value falls back to 1 that often, here I would assume that something is wrong with the way the binding interprets the data.
Edit: Manually creating a new item and binding it to the channel also doesn’t work…

It seems like it might be a binding problem. I can’t help with that.