It seems node red is not refreshing the entities from HA anymore.
"Entity could not be found in cache for entity_id: cover.shelly_shsw_25_001234"
(Node-Red is able to find other (older) entities)
In the developer section of HA I can find this entitiy without any problems.
Is there a way to force an entities refresh inside Node-Red ?
Restart the addon from the supervisor tab.
That worked. Thank you.
I know for sure that I have restarted HA at least once since I had the problem. Are HA add ons not restarted whenever restarting HA itself?
You’re welcome - glad it worked.
To be honest, I don’t know exactly… the addon log would indicate so, but restarting the addon has a different effect on the addon than restarting HA 
Yes. so it seems.
Well, I’m glad you helped me out! Thanks man!