One of the electric couplings I had to fix this week on my brand new Digital had a blue plastic sleeve over the metal blade. This sleeve was so long that I had to really shove the coupling together to make it stick. The sleeve seemed to be a bit too long to allow the connectors to sit right. I needed to squish the plastic a bit.
My theory is that the scrunched up plastic relaxes, unscrunches, and pushes the coupling apart after assembly.
most excellent theroy. hope you are smoking