Internal Error when linking an Org Identity to a CO Person

Attempting to link an Org Identity to a CO Person returns a 500 Internal Error.

1. Search for an Org Identity and view their information.
2. Under "CO People", click on "Link to ... CO Person"
3. Search for the CO person to link to, and click the Link button next to that CO Person.
4. Confirm the linking.
5. This returns an "Error: An Internal Error Has Occurred." message instead of linking the Org Identity to the CO Person.

From the web server log, the call is a POST to "/registry/co_org_identity_links/add"

Stack Trace:

"2024-05-20 17:26:55 Warning: Warning (2): foreach() argument must be of type array|object, bool given in [/srv/comanage-registry/lib/Cake/Model/Model.php, line 1885]"
Trace:
"ErrorHandler::handleError() - CORE/Cake/Error/ErrorHandler.php, line 230"
"Model::_doSave() - CORE/Cake/Model/Model.php, line 1885"
"Model::save() - CORE/Cake/Model/Model.php, line 1754"
"Model::saveAssociated() - CORE/Cake/Model/Model.php, line 2515"
"Model::saveAll() - CORE/Cake/Model/Model.php, line 2287"
"StandardController::add() - APP/Controller/StandardController.php, line 141"
"ReflectionMethod::invokeArgs() - [internal], line ??"
"Controller::invokeAction() - CORE/Cake/Controller/Controller.php, line 499"
"Dispatcher::_invoke() - CORE/Cake/Routing/Dispatcher.php, line 193"
"Dispatcher::dispatch() - CORE/Cake/Routing/Dispatcher.php, line 167"
"[main] - APP/webroot/index.php, line 96"
"2024-05-20 17:26:56 Error: [MissingViewException] View file ""CoOrgIdentityLinks/add.ctp"" is missing."
Exception Attributes: array (
"  'file' => 'CoOrgIdentityLinks/add.ctp',"
)
Request URL: /registry/co_org_identity_links/add
Stack Trace:
#0 /srv/comanage-registry/lib/Cake/View/View.php(470): View->_getViewFileName()
#1 /srv/comanage-registry/lib/Cake/Controller/Controller.php(968): View->render()
#2 /srv/comanage-registry/lib/Cake/Routing/Dispatcher.php(200): Controller->render()
#3 /srv/comanage-registry/lib/Cake/Routing/Dispatcher.php(167): Dispatcher->_invoke()
#4 /srv/comanage-registry/app/webroot/index.php(96): Dispatcher->dispatch()
#5 {main}