Hi,
this label is taken from the Displayname of the corresponding Datasource. If you change the Displayname of the Datasource in the SiteArchitect also this label will change.
This behavior is a little bit unpredictable if you have multiple datasources based on the same table template. Then it is not clear which display name will be taken.
I had the same problem a few weeks ago and will also create a bug ticket, because I think that’s not a good and understandable behavior. Especially in the case where you have multiple datasources based on the same table template.
Greetings
Sandro