I'm having this issue to where I can snap to the first object and the grid and snapping is fine, but when I try to snap the grid to another object, the snap goes haywire and ghost snaps to a "ghost objects" and starts moving cross the map. Turns out, it was the addon "G-water" that was causing it. Not sure if anyone else has come across this issue, but figured might as well make it public (as I already did the trial and error of disabling the possible addon affecting it ) as to help anyone that may have experienced this issue. I'm going to look further into "G-water" to see if there is an option in the settings I can turn off to see if I can keep the addon so they both can work together, I will also let the creator of "G-water" know.