Problem with LoRaWAN and DAC in the same time.

[MRebo.1]

Hi guys. When I program the device with LoRaWAN and DAC with pin extern (PA10), I saw in oscilloscope that DAC stay high every when has uplink. Like the image:

 

Does anyone have any idea why this happens? Thanks!

[Tesla DeLorean]

Perhaps some issue with the grounding? Any obvious shorts or points of connectivity?

Is this some custom board? Is there are schematic for it?

[MRebo.1]

I use the DAC for the COMP. The DAC Pin is not connected to anything, I just keep measuring it to see the behavior of my firmware... I can't send the schematic :(