Deleted title just reappears

[NorthLight-EWR]

If I remove the title in the linear widget ("Temperatur" in my case), then it is gone, OK.
Now, If I reopen the configuration again for the widget, there is "Temperatur" again and if i do not delete it, it is visible again.

Seems to me, that the logic is missinterpreting the empty field as error and inserts the devices' attribute again as title?