Oh man, that is exactly the kind of headache I'd end up with. Did you at least get some satisfaction from finally getting it down? It's wild how long random stuff can just sit there before someone actually takes responsibility for it. I swear half the junk in my yard came from a previous tenant who just vanished into thin air.

Moisture in the mounting tape could change the angle over time, ever think of that?

Did you check if the leak only happens when it's actually raining, or could it be a pipe issue that just seems worse in wet weather? I've seen roof leaks that look like rain problems but are really just old flashing or a cracked vent pipe letting water in slowly. Just something to rule out before you climb up there (roofs are scary, honestly).