I can confirm this apparent bug in CC 756 for Mac. The issue was also present in previous versions. Here is a repeatable method to replicate and demonstrate the idiosyncrasies:
Open CC. Set Grid Spacing to .25" and hit “OK”. Make sure View>Snap to Grid is checked. Draw a 1" box. Drag it around and note that it correctly snaps to the .25" grid. Save the file and name it “Grid Test .25 inch”
Quit CC. Open CC. Set Grid Spacing to 1" and hit “OK”. Draw a 1" box. Drag it around and note that it correctly snaps to the 1" grid. Save the file and name it “Grid Test 1 inch”.
Quit CC. Open the first file (“Grid Test .25”). Note that the visible grid is still 1 inch. But if you drag the 1" box around, it snaps to an invisible .25 inch grid.
As @mhotchin said, to “fix” it, you now have to open the Grid Spacing dialog (where it will already say “.25”), and hit “OK”.
The reason this happens is there is a file called “settings” in the data directory. That file gets updated and that is why when you open a new file it is the job set up for the last job saved.