Quote Originally Posted by Kobal2fr
It's NOT a bug, it's a feature (no, really, no irony in that sentence, for once). Archers and arty will chose their own targets if you select them as a group and order them to fire at one unit.

In that case, the game group automation takes over and assigns each single unit a single, best target, out of the same code that lets you order a full charge of your battleline with a single click, pairing your units with those of the opponent.

If you want archers or arty to fire at a precise target, give them the order separately.

If still the archers/arty won't fire at the target, it's because either they don't see them, or can't get a good "firing solution" because your own men are in the way, or there's an enemy just on the edge of their skirmish range (that part is mostly true for javelins and IS slightly buggish, but it was already there in Rome, and was worse in MTW since back then javelin range was shorter than skirmish range. Just toggle skirmish off and turn it back on when there's a real danger to be overrun)
In that case it's a bad feature. It should be changed (Or at least made optional). It makes sense for melee troops, but not for missile troops (Which you OFTEN want to concentrate on one enemy unit until it breaks).