Not sure one rainy night at Sparks Lake proves much of anything honestly. A tent fly that soaks through could just mean the coating wore out or you pitched it so the tarp wasn't touching and the fly was catching all the runoff. Tarps do work but they flap like crazy in wind and condensation gets bad underneath if you seal it up too tight. Sounds less like the fly is junk and more like you found a cheap backup that happens to work in one storm. Keep both and test it a few more times before you ditch anything.

Watched a line cook get chewed out for salting a steak before it hit the grill, and that steak came out better than anything the chef sent. Turns out seasoning early lets it sink in instead of just sitting on top. That guy runs his own kitchen now.

Had a similar thing happen with my nephew's Honda Civic last winter. He swore it was the transmission because some forum said so, spent two weeks reading codes and watching YouTube. Turned out a $12 coolant temp sensor was making it shift weird. The car ran fine after that but he never did trust the scanner again.