I don't see 4.16 vs 4.2 as being that big of an issue. If this was a $75 lipo, yes, it would be an issue, but not with this one. It may straighten out on its own over the next few cycles too.

If it stays low and you are sure its the same cell that's staying low, you can try charging that cell directly thru the balance wires. I rescue low voltage lipos this way and some cells it fixes, some it doesn't.