Steps to reproduce issue

1. Create a cohort, for example "COHORT1".
2. Create a course.
3. In the course add enrolment method Cohort sync.
4. On the Cohort sync page set the following:
   1. Custom instance name: COHORT1
   2. In the Search box under Cohort, type "COH" and select COHORT1 when it appears. This should now be listed by Cohort with an 'x' to delete the selection.
   3. In the Search box under Cohort click the drop-down arrow and press <Esc> to close the drop-down list.
   4. Click Add method.

Expected results

The cohort sync enrolment instance is added.

Actual results

The red message "- Required" appears by Cohort even though this is selected (see attached Screenshot from 2021-12-06 16-45-13.png).