IR UP6-15 compressor, oil coming out of air filter

So I have a Ingersoll Rand UP6-15-125 screw compressor that is spewing oil out of the intake air filter when it has finished loading and starts to unload. Basically it blows out a couple quarts in a second or two, and I shut it down before it blows everything. I read on another forum about a user had an airend seal go bad and it was letting oil back through the inlet when it finished loading. When he had the seal changed it was fixed. Could this be the case. Or likely something else? The compressor is not very old (2 years), it has maybe 500 hours or so in a educational facility and it is not running constantly.