We had this happen on our 560. After 5 weeks of HP support and 3 visits from techs, they said it must have been a bad batch of perf. Then is started happening on our photo paper ,as well as, damaging our smooth banner for retractables. HP finally sent a level 3 tech out and he spent 2 weeks basically replacing everything but the chasis.. Still couldn't stop the material from wrinkling and getting damaged.
If we set the heat low enough, interpass delay all the way up, and ran higher than 12 pass with like an 80% saturation, we could get a washed out print not suitable to sell. It also took forever to get a print done that way, no way fast enough to do a long run of stuff.
Yesterday, HP finally agreed to buy back the printer. It's great that they stood behind their product and tried, but good riddance.
I know the 560 is different from the 360, but the vacuum wasn't the issue for us. Lifting the blue lever to relax the media is a good start for sure but make sure your heaters are all running the same temp, I guess they can get out of sync.