The Obanakk heavy blade tennogen skin's holster position is bugged when equipped on heavy axes. This issue only happens with heavy axes, that being the Sarofang, Scindo, and Zenistar weapons. This issue does not happen for any of the greatsword type heavy blades.
The Obanakk will remain in the Warframe's hand instead of being holstered when this skin is equipped to the aforementioned weapons. This happens in both non-combat spaces (orbiter, relay, dojo) as well as in missions. Even when a primary or secondary is equipped and in use, the melee weapon will remain in hand as well. https://imgur.com/a/WbGuPRk