Board Thread:Spoilers!/@comment-27060727-20171014181959/@comment-25733960-20171017010346

She could appear at the very end of 7x09 as a cliffhanger (for whatever reason).

Like Cora in 2x02, Ariel in 3x06, W!Robin in 6x10, Black Fairy in 6x16 and Belle in 1x12. All of them appeared in present time at the very end of the episode

Considering 7x10 might have a portion of her backstory, I'd say it's likely

The flashbacks this season seem to be pretty linear