Thank you for your answers.
I am sure, that there is a current limit in order to not demagnetizing parts of the magnets, but it may very well be that high, that it will have no practical importance for the normal kind of BLDC motors used for drones and similar. In worst case you will have to apply the current in a way, that will force the magnetic field in opposite direction than what the permanent magnet supply.
Brushed DC motors with permanent magnets are normally designed so the magnets will not be damaged by the stall current. If you got a DC motor specified for max 24 V DC, you will get the stall current when you apply the 24 V and block the rotor. However, if you have the motor running full speed, and put a reverse voltage of 24 V on the motor, many such motors will be damaged. Then you got the EMF from motor and the supply of 24V making just below 48 V driving voltage trough the resistance of the windings. In this case, the short term current can be sufficiently high, that parts of the permanent magnets will be demagnetized. The stall current of a brushed DC motor is normally about 6 times higher than the thermal nominal full speed current. So a short time current of about 12 times the nominal current will damage such a motor, and it will be before any thermal problem becomes a problem.
I have looked for some information on these drone motors, and it seems quite common, that they get damaged by heat, and it fits your description. But I guess that it is normally the insulation of the cobber windings, that is damaged.
Have temperature classifications on the enameled cobber wire used been an issue for selecting drone motors?
This is a link explaining a bit about that:
https://www.linkedin.com/pulse/13-understanding-insulation-class-enameled-8etge
The temperature rating given is for quite long time use, so the insulation can withstand higher temperatures short term, but there is limits to that. But no doubt, that a class B cobber wire is cheaper than a class H wire. There is an old saying, that a 7 degrees C increase in motor temperature will cause half the life time of an electrical motor.
I am well aware, that you use higher PWM frequency than the electrical period frequency of the motor speed. The two situations I mention refer to any split time situation. But you might need to use situation 1 all the time for FOC in order to place the current vector accurately. With situation 2 you force a specific direction of the current vector unless current in free wheeling diodes are involved.
I guess, that some PWM hardware timers of the microcontroller are somewhat involved in how the six switches are controlled. Do you know some good sources of information about how this hardware is designed for FOC?