Hello fellow connoisseurs of Music and exp. helloooo to my fellow Linux enthusiasts 
Ive installed ansible tidalcycles standalone edition on Ubuntu 24.04.3, Kernel 6.14.0 with no hick ups.
In addition Ive installed Pulsar and TidalCycles official AddOn.
As I use pipewire with pipewire-jack, I cleared the conflicts of the new dependencys that got installed, masking the jackdbus.service so it wont interfere.
My SuperCollidor/startup.scd is based on the official example from Sclang Startup File | SuperCollider 3.14.0 Help but with the suggested “Server.program = "pw-jack scsynth";” Ive found online.
My superdirt_startup.scd is loaded from a startup.scd “Archive.archiveDir = "~/Music/Tidal/".standardizePath;”, and is based on the example file https://raw.githubusercontent.com/musikinformatik/SuperDirt/develop/superdirt_startup.scd that is intended to only have one session (with the “~dirt.stop;” and “SuperDirt.default = ~dirt;” commands).
TidalCycles in Pulsar is set to not AutoStart SuperDirt.
Starting startup.scd via SC IDE App, opening the superdirt_startup.scd, CTRL+A, CTRL+Enter → et voila, everything is running as intended, Pulsar TidalCycles connects successfully to SuperDirts Port and up on eval sound is emitted.
Great.
Now: I CTRL + . or hush to stop all eval, open SC IDE GUI, Server → Quit Server → check my process managers or use ps/px grep and similar commands if any sclang, scserver or scsynth exists → no everything is clear →Start Server again, go to superdirt_startup.scd, CTRL+A, CTRL+Enter →Server Killed with Error 137.
ChatGPT 5.2 Thinking went up and down with me for 8 hours! Not kidding! It suggested me various mods to superdirt_startup.scd in an attempt to prohibit race conditions of already booting servers maybe booting twice, but there is no solution yet.
The System clearly is not Out of Memory having 20GB in spare and there would be free swap that is not even touched. There are no logs indicating SIGKILL by my OS. For cross-reference I limited ~dirt.loadSoundFiles; to the bd files, saving 450mb of memory and only using a couple of MiB, but that didnt helped either.
Imo the SIGKILL (Error 137) must come from SC or SD.
The behavior is 100% predictable and only the very first Start of SC+SD works after a full system reboot: Killing Processes, clearing memory/swap, Logoff User, nothing helps.
Before I post logs or my .scd files please advise me the exact steps I should take (activate verbose, create logs/dumps by SC/SD/Tidal Apps) to provide the right infos bevor I blindly post too much of what I believe is right.
Thanks a lot in advance for your help!