[LAU] Behringer X32 - glitch problems

Hi, I've been playing around with an X32 recently, and it starts glitching really fast. Like, if i start JACK on my internal sound card (2ch) and SuperCollider with 8 to 24 channels, routing all channels to the 2 outputs, everything's fine. But if I use JACK on the X32 with 8 channels and SuperCollider with 8 channels, it starts glitching as soon as the load increases just a little, using the same programs in the background (ScSynth, SBCL (Common Lisp) using Incudine for OSC scheduling). I've found some settings that work ok-ish, but I still have to be careful not to play too many things at the same time. Using the internal sound card, there's much more leeway. I'm working on Arch Linux, using the latest RT kernel with all exploit-fixing options disabled (https://make-linux-fast-again.com/). No, I'm not using these options for my day-to-day work :D . Has anybody encountered this before ? And maybe knows some way to mitigate this ? Best, Niklas