Dear Jet-Pack (IPACS)
With Aerofly FS 4 (December update), macOS.
Prepare a flight plan from Amsterdam to Madrid for exemple (800 NM). Voluntary choose to cruise at FL330. Put the A320 ready to takeoff.
Use Skip Time.
Everything is OK until you Skip Time brings you to the defined cruise altitude. In this case, at each Skip Time action, the cruise altitude will be increase of 1000 ft. Until reaching FL390. At FL390, the next Skip Time action will maintain FL390 but will set FL CRZ to 40000 ft.
It happens whatever the flight you make, even if you chose FL390 as cruise altitude, even if you start from cold & dark.
It is bearable because when you use Skip Time until reaching descent you retrieve your way (appart the MCDU message that says 40000 ft has been set as cruise altitude).
The initial version of Aerofly worked OK, it appeared a few versions before December.
One more thing, my Mac as 16 GB M1 GPU/CPU memory, Aerofly uses 6 GB, so you can strike the heap. The M1 architecture accept a memory use that goes over the memory size, so you can target something borderline.