This is according to Tampa Bay Comic-Con, which shared a Facebook status explaining how WandaVision star Paul Bettany had to cancel his appearance at the convention in order to film the upcoming Disney Plus miniseries. Bettany previously described WandaVision as "f***ing bonkers" (in a good way).
Though production on WandaVision technically wrapped in March, it's likely some of the cast is returning for reshoots and pickups.
Can't wait for this series!