AMD 455 call options not assigned — a bit puzzled.

I usually trade 0DTE index option spreads (follow u/papakong88 's strategy). On some Fridays (and some Mon and Wed for names like TSLA/META) will sell 0DTE equity option spreads. On Fri 5/8 had a large short position in AMD call spreads and had to scramble very hard in last 10 min of trading due to AMD crossing 450 and then 455.

Was short 40 AMD 455 calls expiring on Fri 5/8– tried to buy it back in the last minute before close on Fri but did not fill. AMD closed at 455.19. After hours for the next 90 minutes except for a couple of 5 min dips to 554, AMD stayed above 455 — actually closed at 461 at end of extended trading.

All calls expired — this was so unexpected. The holders must have called in to avoid auto exercise. But all 40 calls expiring — did not expect that. I might have expected 10 or 20 to be assigned.

I called Schwab twice on Sunday to confirm there was no assignment — wanted to have a way to handle the assignment in Sunday night trading itself by closing any short position — it is 1.8M notional short amount. Schwab confirmed all the 455 calls expired. I don't see any AMD short position in my account. Fingers crossed that Schwab does not post a late assignment tomorrow morning.

AMD hit 470 at ~5:30PM Pacific on Sunday. This whole episode is very puzzling.