Cm2350 combustion in cooling system

[Petegraintrain]

Isx15 cm2350 dropped a liner at 350k miles got an inframe they did the counterbore and set liners to 14 thou. Then at 435k miles cracked the head. So replaced that. Liners were perfect. Now at 545k miles I have combustion in my cooling system again. Truck is demanded. Oil temp sits around 210 will climb to about 225 on a big hard pull. Boost peaks at about 31-32 psi. Post turbo pyro never gets over 950. Usually only 850 on a hard pull. What the heck is going on?? Possibly cracked head again? How likely is a dropped liner after being counterbored? I ordered the inline 6 adapter so I can email Rawze my file just waiting for it to show up. What else would cause repeated cracked head other then over boosting?