Export Selection as Premiere Project greyed out

[footagehead123]

I have a project with merged clips (video and location sound). I have a sequence populated with these merged clips (when dragging into the sequence, it's the master video clip and master audio clip and not a nested sequence). 

When I select the sequence in the project panel, go to Export, the Selection as Premiere Project is greyed out and I can't seem to access this feature. I'm not sure why, it has always worked before in previous versions of Premiere. 

Premiere Pro v15.2

2019 Mac Pro

Thanks,

Joseph