Nope that was my first thought to check lol. It was a veil proxima survival. And confirmed that turning on and off one of my two channeled abilities affected ammo consumption. My guess is there isn't really any natural way to have 2 channeled abilites on any warframe, and it seems desecrate is somewhat inconsistent with how it acts as a channeled ability. So this is kind of an outlier rare scenario (it is repeatable however) that wasn't tested for. I think I could try subsuming gloom onto ivara and giving it a go as well to confirm. Again I'm really looking more for clarification I don't want to get tagged for bug abuse lol 😅 because this seems broken.
EDIT 11/30/23
It appears this has been fixed now and was in fact a bug 😁