I was doing some dry firing with my M&P9 and a Trijicon RMR.

went to put it back in the safe and it fell and hit the floor. No damage but I looked at the red dot and its now left of the iron sights.

Any idea what causes a red dot to shift on impact? The iron sights dont appear to have moved.

Feel like for the price it should retain zero when dropped.

Is your mounting interface okay?

Seems fine. I have not taken it to the range so Im not sure if its the dot thats off or if one of the irons got bumped.

2.0?

Original 1.0, pro series with the milled slide from the factor. It has suppressor sights on it.

I had a 2.0 milled for a RMR and have an odd occurrence where the dot shifts left slightly off the irons when dry firing. Everything is tight and I can’t figure out what’s happening.  Unloaded, rack the slide - dot sits right on top of front sight. Pull the trigger - dot drifts left. Rack the slide - dot goes back to center. It only happens when the slide is racked and trigger is set. When it’s in that condition, I can move the slide left and right slightly on the frame and the dot moves back and forth to the two positions above.  It really bothered me, however when actually shooting it happens to so fast I don’t notice it and I’ve never shot better with any pistol in my life, so I’m not worried about it any longer; just an odd thing I couldn’t explain.

Try doing same with yours and see if dot moves slightly when dry firing, then returns at slide reset.

The only time I’ve had an issue with an RMR is a shift from a hard drop. I don’t fault it for it, if it’s still working and can be rezerod and holds zero I don’t consider it a failure. I’ve had a lot of very high end and “robust” mechanical optics shift from a hard fall so for an electronic sight to do it, whatever. It takes a pretty hard hit for one to shift too, a hit that could easily shear off an iron sight of hit right too.

Go shoot it and see if the POI moved.

You have no identified problem until you confirm it on the range.  You need to shoot your gun to see if you actually had a POI shift.