Just failed solo Profit Taker because 0 Manker spawned

[BlackVortex]

are the Terra Manker spawns during Profit-Taker phase 4 removed?
I had to wait 3x 3-4 minutes for my Archgun to come out of cooldown, meanwhile running around trying to find Mankers to get a cooldown reset only to find out, 0 of them spawned during the entire 15 minutes

this must be one of the most frustrating situations I've been in during my WF playing days.

I literally just flew away from the profit taker waiting for the cooldown to be over because I couldn't damage him because Archgun cooldown and no Manker spawns to reset it

15 minutes out of which 10 minutes I couldn't do anything to progress the mission

I had him at the last stage where I just had to finish the boss with the Archgun with about 2 minutes left, only to find out the Archgun was still on 2:30 cooldown (because no Manker spawns)

by the time I hit 15 minutes and the bounty failed I still had 30 seconds left on the cooldown
my average completion time with cooldown resets is around 6 minutes

Went in again, switched to Velocitus because with that weapon I never have CD's, and noticed again that 0 Mankers spawned, so no cooldown resets.

so is this a nerf or a bug?