We fixed a bug with course creation whereby the default course role was given regardless of whether it should be.
Essentially, in order to assign a role, you need two things:
1) The moodle/role:assign capability; and
2) The ability to assign the specified role (Site administration -> Users -> Define role -> Allow role assignments)
Unfortunately the default "Course creator" role has neither of these.
There are a few other parts to this but they should not normally be fixed by an upgrade script. We do not change either the capability assignments, nor the role configuration of an installed site (normally).
I've created MDL-66683
to address this for 3.8. We may need to consider adding this to stables in an upgrade step, but this is unusual for stables. I suspect we should accept such a change in our next minor release and grant the assign to the coursecreator archetype for the current default role only.