Random audio stuttering with Pluto IIx

[naadofett]

I recently installed a Pluto IIx into my gamecube and after initial testing, everything seemed to be fine. The only other mod installed is a region-free switch hardwired to the mainboard (not xeno, etc). I booted up the cube today and noticed that GC menu sound was audible, but stuttering. If I boot up a disc while the GC is acting this way, the game audio stutters as well. Resetting the console via reset button doesn't change anything. If I completely shut off the console and turn it back on, it's basically a game of roulette to see if the sound is normal or not. In my testing, I'd say about 80-90% of the time the console boots, audio plays normally. I'm confident with my wiring (I'm not using a flex cable for the pluto board).

I've tested this both through a Retrotink 4k and directly into my PC monitor with headphone jack. It's almost like the audio signal isn't syncing properly every time? Has anyone else heard of something like this or have any ideas whether it's solvable or not?