Hi all, I ran guix pull and system reconfigure today, updating my kernel to 5.19.12. On rebooting I was unable to get much past the bootloader before the screen started flashing. Aparrently there's a regression in 5.19.12 that couses this issue in some intel laptops. Because guix is guix I just rolled back for now.
This regression was fixed in the 5.19.13 stable release. https://www.neowin.net/news/beware-linux-kernel-51912-could-damage-your-intel-laptop-display-literally/ shows the effect on someone elses laptop (not guix). They say that 5.19.11 works fine and while I haven't checked that myself, I can say 5.19.9 works fine.
