Bizarre Locator Behavior

This one is a first and really weird. I programmed into the locator window 56.4.3.0. But the cursor went to 57.1.3.0. Assuming “pilot error” the first time, I tried again and several times afterwards and each time, the cursor refused my locate point and went to the second locate point.

So I manually moved the cursor back from 57.1.3.0 to 56.4.3.X (whatever was in the ball park) and the cursor stayed there. So then I just added the zero digit to the end and got on with my project. But every single time I tried to just punch in the numbers, it went to measure 57.

THIS DOES NOT HAPPEN ON ANY OTHER SET OF LOCATE NUMBERS! So is there some special hiccup that I don’t know about between 56.4.3.0 and 57.1.3.0? That was really strange!! Any ideas what caused this behaviour?