Could it be the blow through slope logic? Popcorn refers to late combustion that dumps fuel into the exhaust. It would be one of the few ways the ECU would know about this happening. EVC/IVO values on MP 10 would promote most blow through during boost.
Looks like the limit is happening spread across MPs 9, 10, and 13. 10 and 13 have lower values until 3000RPM. After that all MP are the same.
Also you are right at the maximum load table values if you correct for BP.
Might be as simple as enabling OP VCT have the exhaust cam rotate back toward 0 sooner to prevent the extra BT from higher boost levels. Or modify the drivability distance table to go to MPs closer to 0 sooner.