Initial angle of each mortar shell are incorrect to the indicated angle in the sights of their respective mortar (check D-44 and M101 too).
Example 1: An issue occuring with for all mortars. Angle in the sight is set to 78.71 deg. while the initial angle of the projectile trajectory is far greater than that.
Example 2: The M2 and Type 53 mortars suffer the same issue as the M29 but not as prominent. Causing precision errors at certain ranges and altitudes.