I think 400TMY was introduced in 2003, so it is at most 8 years old. The previous owner always kept the stuff in fridge. I always kept the stuff in fridge. I moved my studio due to expansion of my photo business perhaps 4 times during that period, and of course there could be some time where the film would sit unrefrigerated during the move. Generally speaking, though, I move film in middle of night and together with expensive wine and cheese, so as to minimize exposure to heat.
One thing I noticed is that the foil bag was pierced so that air could get inside. But the film wasn’t fogged or anything. What's noticed are huge grains, poor shadow details, and poor resolution. Maybe the film deteriorated due to air even at 2 degrees centigrade over at most 8 years period?
I also processed Delta 400 that was sitting in a camera for 6 years. It had poor shadow details and very grainy look, but it wasn’t as bad as this freshly exposed 400TMY.
Why do you prefer HP5 Plus over 400TMY-2 for outdoor shoots?