First off, I do read the manual - honestly !
For some reason, I've set a mode, or done something unknowingly and when I copy paste beats in a pattern - from one pad to another, they always paste one grid block later than they should. If I'm copying a hi-hat pattern, this also forces the pattern to get longer by one bar just to accommodate that single hit that falls over the bar.
It didn't used to do this, I would copy paste from one pad to another all the time, and the pasted content was lined up just like the original. I don't do anything differently than I ever did. So what setting went fubar?