Absolutely, just as some "Christians" are cultic. And by cultic I here refer to the belief that the Messiah (Christ) is not fully God (Eloah), because without that belief salvation is not possible. The key doctrine of the Messianic-Christian faith is that Yahweh-Elohim manifested in the flesh (incarnated) and became an atonement for our sins. Only Almighty Eloah (God) is capable of doing that, for anything else would not be an infinite atonement and our salvation would ipso facto be incomplete.

At this point I should point out that not all Ebionites (those who reject Paul) are Arians (those who claim the Messiah is a demi-god or just a human being), but there aren't many of them. The mystery of the incarnation, though explained by the other apostles, does not receive quite the same in-depth treatment as that given by Paul.

There are many Messianic cults, sometimes collectively called the Yah Cult though I am myself a little hesitant to associate Deity with cultists, who use His Name liberally. The fact that a person or a group uses the correct Names of Deity doesn't mean they are necessarily doctrinally correct or even saved. There are plenty of Yahwists whom I wouldn't hestitate to place in the same camp as the Jim Jones' and David Koresh's.

To be a Messianic doesn't mean you're saved, any more than being a Christian does. To be saved depends on whether you are truly in the Messiah (Christ), and He in you. And if He is, your fruits will make that perfectly obvious. The saved recognise one another.