In my experience, even this simple connection can cause issues.........
In the main, these can occur by using worn or pattern parts..........I have had past issues of having a fully-tightened (pattern) acorn nut that has seemingly not compressed the HT lead and washer firmly enough down to make a positive connection...........similar can also occur with worn old parts..............
If all is perfect, there is no need to solder the HT lead onto the split brass/copper washer to make a perfect connection.........simply splaying out the copper-core wires across the washer face is amply sufficient...............
Same here.
Generous amounts of contact grease ( lanolin based ) inside the pick up to keep the water at bay and an O ring fitted on the HT lead then rolled down to the top of the cap to stop water running down the HT lead.
