In portal attempt to share with reporter throws "failed to update request participants field, error"

Issue Summary

If a user A creates an issue and a user B is added as the participant, if user B inherits the issue and is made the reporter but not removed from the request participant field, all attempts to share the issue in question with other users from the customer portal will throw the error seen below:

Steps To Reproduce

1. Create an issue as User A in a JIRA Service Desk project.
2. Add a user B to the issue as a request participant.
3. Modify the reporter field from inside JIRA (as an Agent) setting user B as the reporter.
4. As a user go to customer portal and attempt to share the issue with any other user(other than user B)

Expected Behavior

JIRA would share the issue with the other user entered.

Actual Behavior

JIRA would throw the error thrown in the image above and if you look at the Network tab in the developer console, it would throw an HTTP 500 response.

Workaround

Remove the user B from the request participant field. Also, if you attempt to add the user from within the JIRA UI, it would alert you correctly that the reporter cannot be in the participant field.