[NOT A BUG] Counters change size when placed in specific way

@Tahidii the functionality is by design, in order to support backsplashes on counters and is not a bug.  We have requested that the functionality be changed in our Build Mode Feedback thread on the forums.  Here is a quote from that discussion on page 69 of the thread:

"regarding the corner counter issue, I think the problem there is when you have a corner counter partially against the wall, the entire object behaves as if it is against the wall, and it changes its size accordingly (as all counter types do when against the wall). I think this was done in order to support backsplashes, and the coding is still there even for counters that don't have them. We might request that it be changed, but I'm guessing that it's tricky. When you place objects up against walls, many of them are actually intruding a bit into the wall because the wall has a thickness that extends beyond the grid line, but the object is sized to fit or snap to the grid. If you don't shrink the object's size a bit in the back, something like a backsplash would be inside the wall instead of against it. What they could maybe do is allow builders to select from and manually place either of the two sizes and also allow us manual backsplash control. I'll add the request to our list."

In addition to posting about it on the forums in the Feedback section, you might also try tweeting a simguru to let them know that this is something that they community desires changed.