Marvel is doubling down on the apparent revelation from Avengers and X-Men: AXIS , and possibly even more.
In what appears likely to be the first in a series of teasers for January's Uncanny Avengers relaunch by Rick Remender and Daniel Acuña, Quicksilver apparently asks "What if one day you woke to discover your entire life was a lie?" again opening the door to the possibility Pietro and Wanda will find out they were never actually mutants.
This wouldn't be the first time the Quicksilver has lived his "entire life" as a "lie" with his sister. Originally introduced as mutant siblings working under Magneto in 1964's The X-Men #4, editor/writer Roy Thomas retconned their origins in 1974's Giant-Size Avengers #1 to be the children of the Golden Age character the Whizzer. That was the status quo for five years until they were retconned back to Magneto kids in 1979's "Yesterday's Quest" storyline beginning in Avengers #187.
2015's Uncanny Avengers series will reportedly take place, for reasons yet unexplained, in an alternate Earth dubbed Counter-Earth. Scarlet Witch is again a key part of the team, joined by Quicksilver, as well as the Vision, Brother Voodoo, Rogue and Sabretooth. The series will seemingly pick up from the finale of Avengers & X-Men: AXIS #9, scheduled for release on December 24.