Stormcaller Arrow and Magnetic Salvo interaction, or lackthereof

I was testing if you could stack up as many Stormcaller Arrows as possible using attack speed and duration, then fire off Magnetic Salvo to get a mega burst on one target. Seems legit because of all the set up you would have to do. But it doesn't work unless all these arrows are in different targets, rather than the same target. No matter how many arrows are stuck in that target Magnetic Salvo only recognizes it as one arrow

This could be intended but I think they need to make this clear in the wording if it is. If it's intended that sucks, just another fun denial. Just throwing it out there, gg, have a good day.