Message popup window is always visible until 'Cancel' is clicked on iPad

Device: iPad iOS 14 SAF 14

Page: /course/view.php?id=[someint]

Replicated steps:

1. click “Participants“ and view the participant list

1. randomly check a participant and select “Send a message“ from the drop-down menu below the list.

1. type a message and click “send message to xx person“

Observed: The message is sent immediately, but the modal window is always visible until “Cancel“ button is clicked

Expected: When the user clicks “send message to xx person“, the modal will close or the text area will be cleared.