New 5F1 done... Issue...

[HotBluePlates]

Replace the cap.

Either the solder joint is bad, or the leg has a break (partial, internal or otherwise).

[SleepLess]

Replace the cap.

Either the solder joint is bad, or the leg has a break (partial, internal or otherwise).

I need to buy one... I don't have any 8uF or 10uF caps in stock, I only had two... 
In the meantime I noticed that the stock Fender layout mentions a cap between the fuse holder and ground and I didn't install one. Should I?
Thanks!

[HotBluePlates]

No. That's a fixed version of the cap usually found on old Fender Ground switches.

It won't do anything you need done.