When firing multiple weapons in a volley, including a weapon with an arc such as a Rocket Array, the arc prediction always shows, even if the target is out of range (and you therefore won't fire).
This can be misleading, since it makes it look like the launcher would fire alongside the other weapons.
This is especially bad if the weapon is a launcher, since those do show explosion predictions only if your target is in range of the launcher.
(Also, not only is the majority of the very few arc weapons launchers, launchers are also the most common arc weapons!)
The confusing thing is that the two parts of the projectile prediction for arc launchers don't behave the same way;
The arc prediction always shows, but the explosion prediction doesn't (and also gets almost completely hidden by the arc projection before it disappears).
It isn't technically a bug, but it is misleading!
Screenshot attached for clarification.