Xorg post-start hook did not run, but logs state it was completed successfully

[keddad]

Describe the bug
When I try to switch GPUs, I get "post-start hook didn't run" error. But everything looks fine, and optimus-manager logs say that hooks completed successfully.

[keddad@priest ~]$ optimus-manager --switch nvidia
ERROR: a GPU setup was initiated but Xorg post-start hook did not run.
Log at /var/log/optimus-manager/switch/switch-20210124T194512.log

System info

• EndeavourOS
• Gnome
• GDM (gdm-prime 3.38.2-1)
• WaylandEnable=false uncommented in gdm config
• I'm running latest stable release of optimus-manager
• Latest nvidia-dkms

Logs

[keddad@priest ~]$ cat /var/log/optimus-manager/switch/switch-20210124T194512.log
[10] INFO: # Xorg pre-start hook
[10] INFO: Previous state was: {'type': 'pending_pre_xorg_start', 'requested_mode': 'intel', 'current_mode': None}
[11] INFO: Requested mode is: intel
[11] INFO: Checking for GDM display servers
[1141] INFO: Available modules: ['nouveau', 'nvidia', 'nvidia_drm', 'nvidia_modeset', 'nvidia_uvm']
[1141] INFO: Unloading modules ['nvidia_drm', 'nvidia_modeset', 'nvidia_uvm', 'nvidia'] (if loaded)
[1159] INFO: Loaded extra Intel Xorg options (0 lines)
[1159] INFO: Loaded extra Intel Xorg options (0 lines)
[1160] INFO: Writing to /etc/X11/xorg.conf.d/10-optimus-manager.conf
[1160] INFO: Writing state {'type': 'pending_post_xorg_start', 'switch_id': '20210124T194512', 'requested_mode': 'intel'}
[1160] INFO: Xorg pre-start hook completed successfully.
[4] INFO: # Xorg post-start hook
[4] INFO: Running /etc/optimus-manager/xsetup-intel.sh
[13] INFO: Writing state {'type': 'done', 'switch_id': '20210124T194512', 'current_mode': 'intel'}
[14] INFO: Xorg post-start hook completed successfully.
[9] INFO: # Xorg pre-start hook
[9] INFO: Previous state was: {'type': 'done', 'switch_id': '20210124T194512', 'current_mode': 'intel'}
[9] INFO: Requested mode is: intel
[9] INFO: Checking for GDM display servers
[40] INFO: Loaded extra Intel Xorg options (0 lines)
[40] INFO: Loaded extra Intel Xorg options (0 lines)
[40] INFO: Writing to /etc/X11/xorg.conf.d/10-optimus-manager.conf
[40] INFO: Writing state {'type': 'pending_post_xorg_start', 'switch_id': '20210124T194512', 'requested_mode': 'intel'}
[41] INFO: Xorg pre-start hook completed successfully.

[keddad]

Apparently, it is a duplicate of #356. Looks like the bug is not related to a DM