Fusion black frame around clip when back in Edit

Morning all,

New to Resolve. Adore it. Been trawling the Forums with little luck about this problem. Forgive me if I missed the answer somewhere.

Did some Delta Keying in Fusion, then went back to Edit, and the clip now has a black frame around it (See pic attached.)

Using the free Resolve 15.
I'm a technical noob also, so apologies upfront for that too.

Thanks very much for your help!

Anyone? Still struggling with this.

Thanks!

Did you resize/transform you keyed footage?
Did you see the black border also in the fusion viewer?
Is the background you use the same size as the footage/timeline?

There are to many possibilities and there will be no good answers without more context and/or Screenshots

Thanks for your reply Michael. Answers to your questions:

- Did you resize/transform you keyed footage?
No.

- Did you see the black border also in the fusion viewer?
No.

- Is the background you use the same size as the footage/timeline?
The backgrounds vary. In the reference image I posted, the background is the same size as the timeline.
I have other clips with backgrounds of varying sizes, and the black frame is still apparent. (Attached more pics below.)