AIM-9X swtiching to AIM-9M after one is fired?

[Grumbles]

Probably a stupid question here, but I’m just trying to setup 4.33 and noticed something different in Instant Action. I’m in Dogfight Override, and long press MSL STEP to switch to AIM-9Xs (or use the OSB). I uncage on a target, fire one off, but now my stores page has switched to AIM-9Ms? What’s the reason for this?

If I’m not mistaken, in 4.32, it would remain on the AIM-9Xs. What am I doing wrong?