Can't save Sequence - Graph is linked to object(s) in external map

New issue just discovered. Whenever I try and save all in a new level I get the error

Recreated my map using only a cube.
So my Sequence contains just a camera and the cube static mesh.

What is happening?
Somewhat common error but a search didn’t result in a solution for me.
What can I try to resolve this?

IIRC, it got something to do with sequence director.

maybe add whatever sublevel your sequecner has actors in it?
or remove the red tracks?

Hi, I’ve the same issue. Has somebody found a solution yet?