Damn, that's an intersting bug
First, can you see if you you click Set Dir and then View that you end up with the same effect in the GMDL viewer.
I assume that yes, so could you post a location for which you are getting this (click Advanced, then Get Numbers, and post zoom, x, y, and min zoom). Also, did Preview 1x and Preview 2x look ok?
And could you upload the map somewhere so that I can take a look at exactly what happened to it.