This sounds counter-intuitive, but you might try installing the counterweights on the back of the dancer bar. This has helped us successfully print on perforated vinyl and heavy papers that had previously been bunching up on our Latex 365.
I think the reason it helps is this: if your skew is not absolutely perfect, the heavily-weighted dancer bar is pulling the media straight, while it's being fed into the print/cure area slightly crooked. This creates a wrinkle that has to go somewhere, and I've found that it backs up into the curing section, and under the printheads. Installing the counterweights means the dancer bar isn't pulling so hard on the media, so the wrinkle is more relaxed, and doesn't work its way up the media web.