Plane slows down and stalls on gear retract.

Watch what happens when the gear fully retracts:
https://youtu.be/4qEfbR4I1Ak

Here is the airplane in question:
https://www.simplerockets.com/c/gp2sQ9/Airplane-3-3
Here is the same issue on a different airplane: https://youtu.be/bTY7qqnRM68

I have no mods
This appears to be a major issue.