That's a vexing conundrum. As most readers know, waterproof garments are treated with a DWR (for durable water repellent) coating that helps shed water. Once the face fabric (the stuff that you see) gets wet, that can effectively seal the breathable membrane, greatly reducing breathability. It also makes the jacket feel cold as any water in the face fabric evaporates, literally refrigerating the user through evaporative cooling. Most waterproof-breathable jackets suffer some wet-out on the surface after prolonged exposure to rain or snow, but we're talking about hours of rain, not a few minutes.
Then again, you do say you purchased an "older" TNF piece. Meaning what? That it had been used, perhaps a fair amount, by someone else? If so, it's entirely possible that the DWR got scrubbed off by excessive washing, dirt, or just hard use. So I'm a little reluctant to blame TNF, although it's possible they had a problem with either a run of face fabric or a batch of DWR.
Anyway, first thing I'd do is try another after-market treatment. Hit the jacket with some spray-on DWR replacement, such as Gore's ReviveX ($10 for a bottle that will treat two to three jackets; www.rei.com). I've found this works well at making water bead up again. Spray it onto a clean jacket, then dry the thing in a machine. The heat helps the stuff bond to the fabric.
If THAT doesn't work...well, you can always try sending it to TNF with a note explaining your dilemma. Maybe they can come up with a solution, or offer to replace it with a newer jacket at a nominal price.