Cummins ISL9 crankcase pressure

We have a 2016 Pierce Enforcer with an ISL 9

It sets high crankcase pressure code 0556 on a regular basis. Has been occurring on a fairly regular basis for about 3 years. It gets a new breather assembly and drain lines cleaned, code cleared and sent on its way. 3 weeks ago the rear main seal literally  blew out of the block. After overpaying Interstate to replace seal and do engine diagnosis, their prognosis was they see no pressure issues with the engine. It has 65k miles and has been doing this for the 30K. I find it hard to believe its an intermittent blowby issue. Any thoughts, experiences or recommendations?