When cleaning my UMC chargeport plug I noticed one of the pins had a broken off clear nubbie thing, missing from the end, as shown on the right hand pin below. It seems not to matter in the operation of charging. Also please admire the clean shiny silver contacts.. you should have seen the number of blackened Q-tips coming out of this job. As you can see this UMC gets frequent daily use on the road, banged around a lot. Tough little bugger. I had thought maybe these nubbies were light pipes for confirming connection or for passing data. But the receiving end pins in the chargeport don't seem to have any matching optical coupling ... so it's just plastic, and apparently unnecessary. So rest easy if you've got busted nubbies. That is all.