with the normal shieldwall for dwarf warriors and longbeards they will go back to proper formation after having been struck by a displacement effect such as a cannon, splash attack or explosion.

with proper formation i don't mean ending the shieldwall ability,
but going back to a nice tight square formation.

this currently does not happen for ironbreakers,
this also effects how much they are effected by missile fire of both small and artillery.
the potential to stop incoming charges wavers if there are large empty spots in the formation.

the best way to deal with it is to end and start the shieldwall of gromril when the game is paused so they go back to proper square formation. but this is not something i always want to put my attention to for every artillery shot, magic effects such as fireball, splash attacks, displacement effects or explosions.