Well, their are several ways to confuse archers, but there are cures.
1. Archery range. When you have a squad of archers, and one is at the range training. Urist decides he wants to train too. Since there is only 1 rance, you get Cannot Follow Order whiney complaint. Cure: More ranges
2. Bolt confusion. When a dwarf tries to get bolts, that are allocated to your hunters. Cure: Remove bolts allocated to hunters. Dump bolts in their quivers. Hunters get assigned generic bolts. Remove the bolts allocated to your archers. Forbid all bolts. This clears the memory of what bolts are reserved for what squad. Reallocate bolts. Reclaim any dumped.
3.Never, never reclaim bolts at the archery range. They will not restack, but your dumb archers will grab one single bolt thats been reclaimed,consider it a stack, and will run around like a idjit with a single bolt in its quiver.
4. Setting some bolts for C, and other for T. Not very good. When you assign bolts for combat, dwarves will grab a stack, place in quiver. Which is good, until it comes time for Urist to practice archery.
A dwarfs quiver if filled always if it has been assigned combat bolts. The only time a quiver is filled with training bolts is when a dwarf picks them up on the way to practice. Does not refill quiver. A dwarf will never swap out bolts, replacing combat with training.
Lets say you produced some training bolts first, assigned them, then later assigned combat bolts. Urist has been happily going to the range, picking up his training bolts, using them all, then going about his merry way, but did not refill his quiver, since bolts were not designated for combat. When you do designate combat bolts, besides training, your little archer will go grab combat bolts to fill his quiver. When it is time to train, confusion now in sues. He already has bolts in his quiver(combat) but needs to pick up his training bolts to practice with. In some cases, you wind up with cannot follow orders, or they will start using up all the combat bolts in stock to practice with. Cure: Assign a specific material of bolt for training. Create a regular barracks for archer squads. Craft them small stacks of bolts to practice with. Have a good supply of combat bolts on hand. Assign combat bolts when they are needed for combat. Unless they are target practicing at the time you assign the combat bolts, they should rush to fill their quivers. The one with a half filled quiver is in trouble, unless you designate the training bolts as C and T.
5. I set them on Active training, and they will not go to the range. Reason is every months order on Active Training to begin with has the Train order. This means Give or Watch demonstrations, Spar, or combat train. More individual training(weapon practice) occurs under either of the schedules, with no order that month. If all they are doing is obeying that months train order, if inexperienced, you will will see hardly any target practice, since will just be listening to lectures. Cure: Under Active Training, schedule them a training month, giving no orders the following 3 months. Now for that year, will have 3 training months, and 9 months of target practice, if you have enough bolts, lol. As the squad improves, maybe go to a training month, followed by a no order month. Repeat cycle rest of the year. By now, should be highly skilled from sieges, killing wildlife, so target practice is not needed as much.