Just an update for your reference, I temporally fix this error by disabling the extension Internal Links No Reload. Now the event can display in the modal as designed.
However, even in a fresh installation without any other extensions, while we can access the event detail page (i.e., yoursite.com/events/1) via the link on the modal, we can't access it directly via the link from any other else, so we can't share the event to other people by using the direct link that created by this extension.
This error still happens when we reload the event detail page after accessing it via the link on the modal. You can check the error in logs file by yourself.
I don't know how to fix this, but I hope this information can help you to figure it out.
Thank you.