I changed the Global Admin accounts permissions to only have Super permissions in one company, previously it was blank so I assume the account had super permissions in all companies. After doing that, I was not allowed to change any permissions for the Admin user or any other user, with it giving the error:
You have not been granted rights to add, modify, or delete this permission set for this user in this company. To obtain rights, you must be granted either the SUPER or SECURITY permission set.
This account also has the SECURITY permission set but assigned to a different company. Another user also with the SUPER permission set (blank company field) cannot edit permissions.
I don't know how to fix this error?