Edit enrolment modal on Participants list fails to save changes gracefully

Steps to reproduce:

1. Teacher / Admin etc. opens course Participants list, clicks the Edit enrolment cog icon next to a given user
2. Teacher / Admin changes some details (e.g. switches Active to Suspended status or modifies the Start or End date of the enrolment period), and Clicks Save changes.
3. Teacher / Admin receives the confirmation alert "The enrolment for ...  has been updated".
   So far , so good; HOWEVER, when attempting to navigate away from the Participants list, s/he receives a pop-up warning from the browser asking to confirm the decision to leave the page as there are may still be unsaved changes (which appears to be false).

Expected behaviour:

After successfully saving changes in the Edit enrolment modal pop-up and returning to the Participants page, the teacher / admin should be able to close the window / tab, or move to any other page without any additional warnings. Based on my tests it appears that the changes made to enrolment details are saved correctly by the modal, but the window does not completely close.

Notes:

• The bug affects 3.11.9 (and earlier); it does not affect Moodle 4.
• I witnessed the same problem whether editing user Manual enrolment details or Self-enrolment details.
• Interestingly, any changes to enrolment details performed with the help of the "With selected users..." > "Edit selected user enrolments" option - save successfully and completely without triggering any additional warnings from the browser.

PS. Was not sure which components to select for this issue.