Event not found error only on classes

Joomla 4.4.10
Jem 4.3.1
Mysql 8.0
php 8.2

Website  ukjive.co.uk   click on a freestyle and it displays correctly.
Go to classes   ukjive classes    and a warning "event not found" appears at the top although the event displays correctly.

I can't find what is triggering it and the only things that's happened recently is a user putting classes on with recurrence weekly for a year and a start and end time 5 years apart. I resorted to sql "set enddates = dates where locid =" to sort it out. I could understand if it caused a problem for that location but it's all class locations.   there's nothing in the error log but a lot in deprecated. I'd be happy just to suppress the message.

Can it be that the word "classes" is reserved for Joomla/Jem?

The site has been working for 6+ months without this problem showing up and as previously mentioned there is nothing in the error log. I believe it is something specific to Jem rather than a joomla thing. I'm going to turn on debugging for a while to see if I can get more information.

Update: turned on debugging - no errors

I searched for the error message and found. components/com_jem/language/en-GB/com_jem.ini719:COM_JEM_EVENT_ERROR_EVENT_NOT_FOUND="Event not found!"
frank@thunderthighs:~/website/ukj2070125$ then I searched for use of the error message and it was only used in components/com_jem/models/event.php   it was referenced three times and the first two were 404's  the third one is in a section to do with event registration  but I don't have registration turned on so it should never get executed.     protected function _doRegister($eventId, $uid, $uip, $status, $places, $comment, &$errMsg, $regid = 0, $respectPlaces = true)    {
    //    $app = Factory::getApplication('site');
    //    $user = JemFactory::getUser();
    //    $jemsettings = JemHelper::config();
        $registration = (empty($uid) || empty($eventId)) ? false : $this->getUserRegistration($eventId, $uid);
        $onwaiting = 0;

        try {
            $event = $this->getItem($eventId);
        }
        // some gently error handling
        catch (Exception $e) {
            $event = false;
        }

        if (empty($event)) {
            $errMsg = Text::_('COM_JEM_EVENT_ERROR_EVENT_NOT_FOUND');
            return false;
        }

        $oldstat = is_object($registration) ? $registration->status : 0;
        if ($status == 1 && $status != $oldstat) {
            if ($respectPlaces && ($event->maxplaces > 0)) {    // there is a max
                // check if the user should go on waiting list
                if ($event->booked >= $event->maxplaces) {
                    if (!$event->waitinglist) {
                        $this->setError(Text::_('COM_JEM_EVENT_FULL_NOTICE'));
                        return false;
                    }
                    $onwaiting = 1;
                }
            }
        }

---

I'll check the database but I don't know what to look for really.

By commenting out the three calls and uncommenting till the site worked again I got to around line 163
# Filter by categories
$cats = $this->getCategories('all');
if (!empty($cats)) {
$query->where('c.id IN (' . implode(',', $cats) . ')');
}

# Get the item
//$query->group('a.id');

// if ($error = $db->getErrorMsg()) {
// throw new Exception($error);
// }
try
{
$db->setQuery($query);
$data = $db->loadObject();

}
catch (RuntimeException $e)
{
Factory::getApplication()->enqueueMessage($e->getMessage(), 'notice');
}

if (empty($data)) {
throw new Exception(Text::_('COM_JEM_EVENT_ERROR_EVENT_NOT_FOUND'), 404);
}