Private jet
A quick look at the physics will tell you that no one is going to move a door in flight if that aircraft is pressurised, so presumably to move this door in flight the cabin was depressurised ?
Knowing the forces imposed on a door, if I had a semi open door on a semi pressurised aircraft the only place I would go would be back on the ground with as little pressure in the cabin as I could have.
Any door that has not closed properly and has had a even a part pressurisation cycle needs to be looked at very carefully by your maintenance team.