That's why you want the silver plated. (With actual silver, Not that 'silver color' crap)

Silver is metalurgically compatible with silver-tin based solder, and it readily tins.

The 'silver colored' wont tin at all, and naked copper often has a tenacious patina that wont accept tinning.

The silver plated works great though.

I have jumpers at j10 located near npu so possibly this is issue.