Totally unscientific, but at my last job we'd store our French press coffees in a hot room just off the kitchen (probably in the 80s). The room was lit by fluorescent lights and had no windows or direct natural light.
They were kept there because it was where the water tower, grinder and presses were stored. Coffee not in "active use" was stored in our wine cellar (mid 60s).
I'd notice something like this:
We'd get a Rwandan in... It would be really great, but after four days of sitting in that hot room it would lose almost all of its complexity.
When we'd worked through the pound, we'd run to the cellar and grab another bag of the same stuff (presumably the same batch, but definitely the same roast date). The cellar-stored coffee seemed to retain its complexity much more.
Coffee in the hot room was subject to infrequent opening and closing of its glass storage jar. Our press coffees were shipped and "cellared" in non-valve craft bags.
I always wondered if the heat was making the big difference.