Seems to be a similar kind of shenanigans to what created the rift between JJ and Stern in the first place.
From a little digging (and someone more familiar with the situation can clarify), it seems the first wedge was selling games to Costco for cheaper than they'd sell to him, despite him being the biggest volume dealer - making it so that Costco's retail price was basically his wholesale price. Second was continuously upping the cost of LOTR LE after orders had already been taken, essentially removing all profit were he to honor the original price. Third was cutting back his LOTR LE allotment despite the fact that he was the one that essentially got it going, so that he was forced to buy Canadian machines from Starburst (ones that nonetheless shipped directly from Stern) simply to fulfill his orders, which ended up creating entirely new headaches because they came with Canadian coin mechs.
Now, from reading the posts I'm not going to claim Jack handled all this as smoothly as he could have - I think he was genuinely ticked off at this point, and I'm sure folks like MrBally who were all over those threads will have their two cents - but it seems he was stuck between a rock and a hard place not actually of his doing. His most logical option was to simply cancel orders and sell what he could at the new price, but in the end he worked to honor prices and scrounge up machines... and got crucified for it.