840 mount is not as snug as my old 530

I just picked up an 840 solar.  I have genuince Garmin out front mounts.

With my 530, it turned in with a bit of tension from friction and was in solid.  The new 840 turns in with almost no tension at all. It does lock into place, but I can slightly rock it.  Is this normal?  I've seen posts where people have the mounting tab actually come off.  I checked my screws and they seem fine.