As it turns out, this sort of thing is a problem....
View attachment 4239125
....so, I decided to fix it.
Which, of course, didn't go like I wanted - before I even really started, that other wire/solder joint just popped off the pot casing.

Just so happens, that's the bridge ground
Then, I decided I didn't like anything about how the grounds were attached, and that I should re-do all of them
Results are not pretty, I'll go back through and clean it up & make it look more proper when I've got more time, maybe tomorrow
View attachment 4239128
But, the grounds are definitely more solid now
Between that, fixing the bridge inserts, and the Nexus strings, the Blackbird is no longer my brightest Thunderbird - it may be the darkest, even more than the Redbird