Animation mirroring behaves differently in import settings vs animator controller

I am getting different results when I mirror an animation in its import settings and when I mirror it in the animator controller (either in a regular state or in a blend tree).

The first one (import settings) acts as intended, mirroring left to right, but the second one (mirroring in the animator) also seems to alter the timing, offsetting the animation in a way that seems to be mirroring the animation in time as well.

The animations does not play backwards, but the events seem to be happening in reverse order somehow.

Is this expected? What is going on?