I got a butterfly bush a few weeks ago from an online seller and it seemed to be doing fine but the past few days I noticed the tips of some of the leaves started to turn black. Any ideas of what could cause this?

I also have another butterfly bush I purchased from Home Depot and that one is doing fine, but the one I bought from the online seller seems a little too viney- are there different types of butterfly bushes (some with branches vs. others that grow crazy) ?

Thank you..!

that looks like some Asclepias to me. Many Asclepias are called butterfly 'something'
Butterfly bush generally means Buddleja, a woody shrub.

Not sure about its' ID, but looks like it needs more (hours of ) light (per day.)

Cynanchum laeve is a butterfly vine- there are several, oppposite heartshape leaves,
Suberosa is another, tho I am not up to speed on that one