USB mic makes popping sound when using CAMERA (video)

Hi! I'm having problem with a USB mic run into the phone (through a powered USB to lightening adapter) making a random periodic popping sound. It happens with two different phones.

--> All cables and adapters have been swapped.

--> All firmware is brought up to date.

--> Extra files and memory usage reduced and experimented with.

--> Mic has been brought further away from the sound source (About 5 ft.)

--> Another mic was tried out

Any solutions or workarounds -- and is there any easy way to use a Yeti or USB mic with the camera that doesn't involve complicated syncing?

Thanks!