Os-prober does not work as it must

You can try to start Manjaro with /etc/grub.d/40_custom
and commenting out os-prober.
This will start the bootloader of Manjaro afaik and not manjaro entry direct.
If openSuse or Manjaro update kernels, otherwise there will be much work to repair…
EDIT:
look for: “chainloader”
(Can't boot into windows after updating)