BMPCC4K and the NTG5

I just got my NTG5 in the mail. Not sure if I got a defective unit or not, but when plugging it into the Blackmagic Pocket 4K, I'm hearing a weird rumbling sound. I tried to replicate it with my Zoom H4N, but didn't hear it. I did hear weird inferences sounds for a moment, though they seemed to normalize go away after leaving it on for 5 minutes. Also plugged my NTG3 into the Blackmagic and everything sounded fine.

EDIT: I found the problem. It's the internal battery. Seems the NTG5 is a little more power hungry than the NTG3, because when I plug in my external battery, it sounds fine. But when I have the camera run off the internal battery, I get the rumble sound from before.

Having to use external power is perhaps a little disappointing but I don't think I would find too inconvenient.
How does the sensitivity compare between the NTG3 and NTG5, is the NTG5 any hotter?

Having to use external power is perhaps a little disappointing but I don't think I would find too inconvenient.
How does the sensitivity compare between the NTG3 and NTG5, is the NTG5 any hotter?

It’s definitely a hotter mic. To compare, I would have to normally set the NTG3 to 80 or 75. The NTG5 I would need to set to 65 or 55. Which is nice that I don’t need to raise the amps high. The NTG3 however I think does a better job isolating the voice from the background. You’ll hear less ambient sound judging from my tests. However, that’s probably because the NTG3 is 2 inches longer, allowing more isolation for whatever you’re targeting. So that’s the trade off. But I’m ok with that. I mainly wanted a short mic that I could rig to the camera, for scratch/backup audio, as well as something easier to travel with. It’s great since it’s super light and short. I think for booming, if you had to choose, the NTG3 might still be the better choice. But if you want something cheaper, and made for more run and gun, NTG5 is better in that area, and not that far behind the NTG3.

I'm also running the NTG5 into the P4K (6.6 FW) and hearing an audible noise floor, even when running off V-Mount power. Have Blackmagic or Rode said anything about yet? Neither my 416 or my NTG2 have this issue.