I have a Hesston 5585, which is nothing even closes to what you have, but had the same problem two years ago, trying to bale some late oat hay that was stemming, but ground was damp. Started the day good, but the farther the day when it kept getting worse. Did get the field done that day. Next day I tried to bale some very dry grass hay. could not get a bale to start at all. Tried everything I could think of, nothing worked at all. Ended up giving up on it for the day. Was so po'd I left it sit outside of the shop that night. Next moring, went out to shop and there was a very heavy dew the morning. Went to the baler and noticed a brownish slim all over the belts. I figured the juice from the oat stalk and dirt mixed and made a slick coating on belts. I powerwashed off the belts, they looked awhole lot blacker afterwards. After that it never missed a start. Sorry long winded, but maybe something to look at.

Tim