JRoute::_('index.php') no longer adds Itemid since Joomla 3.8.4

Question

I have a custom component that handles generates a page containing a list of events, and a page giving details for the event. Previously, I would have one menu item setup to handle the list page:

Code: JRoute::_('index.php?Itemid=102&component=com_event&view=events');`            
Result: /index.php?Itemid=102&option=com_event&view=events
SEF: /events

To handle the url for the details of specific events, I would use simply use the following:

Code: JRoute::_('index.php?component=com_event&view=event&id=1');
Result: /index.php?Itemid=102&option=com_event&view=event&id=1
SEF: /events/event/1

Since Joomla 3.8.4:

Code: JRoute::_('index.php?component=com_event&view=event&id=1');
Result: /index.php?option=com_event&view=event&id=1
SEF: /components/com_events/event/1

The Itemid is no long included automatically. This creates an issue with the active check on menu items. Is there a way to fix this outside of editing every single instance of JRoute to manually include Itemid?

Answer 1

There seems to be a bug with the routing in Joomla 3.8.4 which is a known issue and is currently being discussed on Github, here:

https://github.com/joomla/joomla-cms/issues/19496

I've seem elsewhere that a quick fix (temporarily) is to replace the following file:

libraries/src/Router/SiteRouter.php

with the one from Joomla 3.8.3

There is also a pull request here: https://github.com/joomla/joomla-cms/pull/19498