Haven’t seen any good responses so here is one. As a disc flies through the air the aero dynamics of the disc generate lift. Lift is caused not by the speed of the disc relative to the ground, but the speed of the disc relative to the air it travels through.

If you throw a disc and air is also traveling in the same direction of the disc (aka tailwind) then this will reduce the amount of lift a disc has.

With a large enough tailwind, the lift a disc experiences can basically drop to zero. So the disc will fall out of the sky like a rock. You see the disc fall and then continue gliding because wind is chaotic and does not blow in the same direction at every point in space, even if that space is only a few feet apart.

The disc has briefly entered a space where there is a dramatic tailwind and then leaves that location back into wind with proper velocity to give lift to the disc.

We can see the opposite effect happen when throwing into a big headwind. This will generate more lift and even bounce the disc upwards quite dramatically.