I doubt that condition happened overnight, but in any case if that showed up on my tent I'd be contacting the distributor (Camera Essentials) without hesitation.
They may have experience with the cause and have resolved it. Check their website and notice the satisfaction guarantee; you could be in line for a new replacement. Did you buy it used or know the conditions of its use? IIRC there was a thread somewhere (possibly on this forum) that talked about the use of insect repellant (DEET I think) that could cause such a condition.
It looks like the damage has been caused by the contact between the "gloves" and the aluminium in the folded position.
Perhaps wet or damp gloves before packing?
Paul, I had this exact same issue and if you run a search here, you will find that this has been an issue for others in the past. Essentially, and for whatever reason, the material begins to degrade and get sticky. That can result in the silver coming off in patches as you have seen. I used mine that way for some time before replacing it, but don't take my experience as a solid promise of performance. This seems to have been some sort of degradation and out-gassing effect.
Eventually, I did call Camera Essentials for advice and they offered to replace mine with the same model at a good discount. I do not know if they will still do that. I've had the new one for about two years with no problems, but I only keep it wrapped up in the storage bag on trips and try to minimize leaving it in a hot car if possible. Otherwise I keep it out in the open air just in case direct "skin to skin" contact is what set this off in the old version.
I would first test yours with unexposed film out in the sunlight and see if you have any fogging. If it's okay to use, treat it as a "for now" situation and don't expect it will last forever. Most of my loading took place in motels at night with dim lighting, so it wasn't a big issue except for the irritation of the stickiness whenever I tried to set it up.
"One of the greatest necessities in America is to discover creative solitude." Carl Sandburg
I've had a lot of rain gear and tents delaminate after several years, I'd assume more quickly if you leave things rolled up and in heat like the attic or car trunk. I don't think any of these kinds of materials will hold up over decades, they are more of a 5-10 year purchase. If they made them from a canvas or similar cloth they might hold up better but they'll be heavier and bulkier, and not as light tight. It's a pity they are expensive but I considering the cost of manufacturing, they aren't out-of-line for their quality level.
I just received my Harrison Jumbo tent from B&H a couple days ago. For what it's worth here are the Camera Essentials new instructions that came with mine.
New Storage Recommendations for all Harrison Tents & Bags
Store your Harrison Tent for long periods unrolled in a cardboard box or bag.
If you have silica packets, put them in the box with the Tent. Use our stuff sack for travel only. The fabric needs to "breathe" when it is stored for long periods of time.
Avoid storing your tent in an area with extreme temperature variations like a car trunk or garage. This can damage fabric over time.
I agree with Frank...and I sure wish I had been given the storage advice when I owned my Harrison tent. I always kept mine in its storage bag (who wouldn't?) and one day I opened it to use it and found the black lining inside had melted into a mass of goo. It was really nasty. For some I have kept the aluminum poles. Robbie
I think they are still at H&H, Will Harrison, 1835 Thunderbolt Dr. Unit E, Porterville, CA 93257, 559-782-0121
Just out of curiosity, how much better is the Harrison Changing tent to this one? Calumet changing room
I have the Calumet one and am very pleased with it, I find it difficult to understand how much better can the Harrison one be for 4x the price.