if you try to manually guide multiple missiles (eg. DAGR) in the same area you will experience, that the first launched missile looses it's target and pulls up into the air and circles, about 2-3 seconds after a second missile was launced.
this happens every time you launch a missile while there is still one in the air.
i know the feature received a tweak in v141362 (Tweaked: Manual guidance of missiles was improved), so i don't know if this behaviour was intended. i sure hope it wasn't, as it makes it very easy to waste missiles.