Unlike rim brakes, discs apply a significant reaction force on the axle. You can see this if you think of the wheel as a lever with point of contact on the ground, the brake and the axle in a straight line. If the disc caliper is forward of the fork blade, the reaction lifts the axle into the dropout and all is good, If the caliper is behind the blade it drives the axle down, which can be a problem.

You can see this for yourself if mount a wheel loosely, apply the brake and push the bottom back as the ground would when stopping.

So whatever brake you have it's important that the QR is secured more tightly than you might be used to doing with rim brakes. You can also help yourself (if the disc is forward of the fork) by mounting the wheel with the bike on the ground. This sets the axle to the top of the fork slot so even if the QR is a hair loose it still can't move higher.

BTW the same rules apply on rear wheels with vertical dropouts.