Alright, I've done some investigation with the Hawk. I couldn't replicate using the MiG-23MFD, so I went back to the mission that I could repeatedly and reliably get the bug: "Intercept" which is provided by VEAO. I went through each aircraft in the mission, deleting one group at a time, restarting the game and playing. For me it was Su-33s that were responsible: If I play the mission with Su33s, I get the superhawk bug, if I delete or change the Su-33s (to Su-30 for example) I get the normal Hawk behaviour.