KME,
Your 1652 is an early model as is my 1653.
Direct from Fluke themselves, they had problems with the early leads so they changed the manufacturer. Look exactly the same, but different build.
I had the same issues with my first set, however, the visually identical set I got a few weeks ago with my 1653B (From MeggerMark) are a LOT more reliable.
However, I feel that the build quality of the KEW leads is better.
I have a set of KEW leads I use for meter checks only which are kept seperate & safe, they ALWAYS check out with the exactly the same values.