HP Pro Satin gets an industry rated 250+ year display rating that may be justified for non critical consumer photo judgements about "easily noticeable fade", but I have documented noticeable OBA fade in less than 20 Megalux hours in my light fade tests (equivalent to only 10 WIR years on display).
I'm sorry to hear that, as it is a top performing paper on an HP Z printer, otherwise. That is certainly a big discrepancy, between 250 and 10 years, based on different criteria.
I thought that OBAs were a concern, but not a particularly short term issue until something recently made me a realize that they are much more a worry than I previously thought. I had a short roll of HP Professional Matte Canvas that I failed to put away and had left standing on end, with a band of acid free paper securing it from unrolling. The roll was nowhere near any direct sun, and only got extremely diffused natural light at reasonably low levels. I had already switched to trying to print all my canvas work on Chromata White, but had a client that wanted the HP canvas instead.
When I went to unroll it, I was shocked to see that the canvas was significantly whiter under the band than on either side, after just over a month's time. At first I thought it must be a flaw in the coating, but then I checked and confirmed that it was the exact size of the area that was covered. Granted, I live on a rock in the middle of the Pacific that has a lot of volcanic gasses in the air, but not enough that it is rotting our lungs, so it is perhaps a factor, but not extreme enough to justify this in only a few weeks time. The vog is largely sulphur dioxide, and is worse some times than others, but I had asthma in California that has gone away since moving here, so I don't find it to be much more than a visual issue. I confirmed that it was the OBA fading at work by putting an ultraviolet light on it. The light area glowed brightly, and the darker area was unaffected. I don't know whether to blame the gas issue or UVs, but either way, it is a significant concern.
I now have joined the OBA/"sky is falling" choir. The HP Pro Satin is the paper that I have been the most reluctant to discontinue, but this news from Mark is another strike against it. I still use some Hahnemuhle papers that have the OBAs cooked into the pulp, but prefer the ones without it altogether. If a client insists, I tell them why I prefer to avoid them, but obviously the customer "knows best" and I print on what they request.
I guess I need to start looking for another smooth satin paper without OBAs. Breathing Color seems to be on the right track, but their papers aren't switched over just yet, and I don't think they even have a smooth satin paper in their line anyway.