Saw the film for a second time today. Reaffirmed that the only figure from this film I’m interested in is Wasp.
Regarding the mid-credits scene where Janet warns Scott to avoid a time vortex and he subsequently gets stuck in the QR after the Pym’s disintegrate, I wouldn’t be surprised if he does indeed get caught in a time vortex and ends up in A1 at the Battle of New York, which would explain the production photos we’ve seen with the Avengers in their A1 suits with him also there in his AMatW suit.
However, it still doesn’t explain the black wrist bands many of them appear to be wearing for whatever reason.
Only thing is he would not know what happened or why since he was stuck inside. He is probably thinking there was a equipment malfunction or something like that and not that half the life in the universe was gone.