Sorry, just to clarify, this noise happens when the node is transmitting. It’s setup as a duplex node, but I eliminated the second radio while testing for simplicity. With everything disconnected other than the fob to the pi and the audio from the fob to the radio (via isolation transformer), if I manually trigger PTT, the noise is present in the signal transmitted. The audio connection is to the correct place (per the numerous bf888s tutorials out there as well as my own validation), and it happens regardless of the power supply used, I have tried several.
I haven’t hooked up headphones yet, but I would almost certainly bet that it’s present on the audio line.