Errors, CATCH and finding the error. Not good

Do you mean Unused Config Nodes? If so then I presume you know the cause and solution for that.

Colin,

Not quite. They are "widgets un-assinged to a group".

No, I don't quite get it.

I have explained (in the other thread) my thoughts on how they happen.
I import a flow/stuff and they have non-existent dashboard names.
They are created to accommodate them.

I then cut/move the items and that "dashboard" is empty.
I press DEPLOY and all is "sweet".

Later I see I have (for instance):

There are 22 widgets not in a group. Click here to create the missing groups

I press the button and "all is resolved".
Until later (when exactly I don't know) but they come back.
And won't go away.

Well, they do if I press the button. But as stated: that is temporary.
As there is no way to see "who" they are and trace them, it is a bit of luck hoping they go away and stay away.

I have never seen that one, sorry.