During parallel runs, mod_scheduler generates 2 errors:

Scenario: A manager edits slots for several teachers, creating conflicts
conflicts.feature:71: And I should see "in course C1, scheduler Test scheduler B"
conflicts.feature:110: "in course C1, scheduler Test scheduler B" text was not found in the page (Behat\Mink\Exception\ExpectationException)

Scenario: A teacher adds a series of slots, creating conflicts
conflicts.feature:127 And I should see "deleted"
conflicts.feature:179 "deleted" text was not found in the page (Behat\Mink\Exception\ExpectationException)