UA 787 N26906 - Broken and going back to the factory?

I was scheduled LAX-IAH on the 787 (N20904) last night, which was delayed hours and then swapped for a 762.

This morning I see they have a UAL7708 flight plan filed IAH-BFI.

Sending it back to Boeing for a fix?

Edit: and now it's in the air headed to BFI, but it's N26906 not N20904.