I’m sure your camera is working fine, but having just performed a test, because I was curious, using a known good working camera, and having just brought it indoors, I can tell you that it is next to impossible to invoke a recording in a mirror. I was leaping around like a fool, with the camera looking right at my reflection, but nothing. As soon as I put my hand in front of the camera, between the camera and the mirror, click, and off it went.
This, I can only assume, is as a result of the glass in front of the mirrored surface, being good at absorbing infrared, hence the difficulty in getting triggers from behind glass, which is a known limitation. However, if the reflecting surface were not a mirror, no glass, just a metal surface, or it was reflecting off the surface of some glass, at an angle, not having had to actually pass through it, then I see no reason why that wouldn’t reflect nearly all of the moving IR image, and thus be able to trigger a recording. I didn’t try that, because I didn’t think of it at the time.