alphaEqn is missing alphac term in MPPICInterFoam
alphac should be added in line 106 of alphaEqn.H in MPPICInterFoam solver.
There is another note to this solver with the usage of MULESCorr during simulations. I think alpha field is not correctly solved without MULESCorr. Without MULESCorr, twoPhasePachuka tutorial crashes at about 0.9s. The issue can be reproduced on twoPhasePachuka case by commenting out MULESCorr in fvSolution, and changing maxCo and maxAlphaCo to 0.5.