Sorry if this has been reported already - However it's really annoying to me.
Seem there is a bug in DB Navigator in case there are external Tables defined in the Schema. This is not an issue in the tree view of Code Editor.
Please see screenshot.
The DB is the same component and querys are the same as well.
Just some bugs there for some reason…
it has been already fixed it in 6.6 beta.
And we will release the 6.6 beta soon.
Thanks again.