It seems when I tried to edit an existing map or create a new map today, the map centering by lat-lon was not working properly. The map came up centered on the Philippines...I'm guessing that it ignored the minus sign on my longitude value. I tried repeatedly to fix this. It finally centered correctly when I entered a simple address for the map center (and let it do the geocoding). And strangely, when I then went back and re-entered the same lat-lon values to try to reproduce the problem, it took the lat-lon values correctly this time! Strange behavior!
Maybe if you have similar problems with lat-lon values for the map center, try entering an address first, then switch to your lat-lon values. YMMV