I don’t know about AI aircarft, but I can see how some GA Planes can easily be flown at the incorrect altitude, when on AP, in real weather, without the pilot even knowing that this is the case. For instance, in the C172 Classic, the AP is using the Transponder’s Baro, AND the transponder’s baro is also not displaying FL, but instead is being incorrectly adjusted by the B key.
An interesting case of TWO PROGRAMMING ERRORS, being able to can cancel each other out !!
That aside, if the SIM ATC thinks that an AI plane is at the wrong altitude, its the SIM’s fault for putting that plane at the wrong altitude, or it is at fault by believing the p;lane is at teh wrong altitude, Unless it its really trying to “SIMULATE” a sky full of inexperienced, rookie student pilots !! 