"Display List of Reviewers from Past Review Rounds" breaks reviewer adding

[cpence]

Describe the bug
Whenever the feature "Display List of Reviewers from Past Review Rounds" is enabled in Manager, the reviewer selection table is unable to select reviewers. Any reviewer selected produces the error message "Select a valid choice. That choice is not one of the available choices."

Janeway version
Unknown! Michigan Press-managed installation and I'm not sure where to find the version number in the Dashboard or Manager. I believe they're running the current release.

To Reproduce

1. Enable the feature.
2. Visit a paper with previous reviewers.
3. Select "Add Reviewer" for a new round of review.
4. Select one of the previous reviewers, leaving everything else at defaults.
5. Click "Add Reviewer."
6. Error: "Select a valid choice..."

Behavior reproduced on Firefox, desktop, Linux and Chrome Android, so I don't think it has anything to do with the web browser in use.

Expected behavior
The reviewer should be added.

[cpence]

Thanks so much!