MFPLI01220S When array cross-sections are used within expressions or an assignment, all cross-sections must have exactly the same bound for each dimension. A lower bound differs in this expression.

Not only must the difference between the lower and upper bounds of each dimension of both operands in an array expression or assignment be the same, but the lower bounds of each dimension must also be the same.
Resolution:
Ensure the lower bounds of each dimension of both operands are the same.
Module:
COMPAT.PL1, VALASS.PL1