Error: Call to a member function format() on null in intercept_messages_entity_insert()

As MR is given so Moving it to NR.

@droath Just so I'm understanding, so you've got some other type of entity that's having messages sent out by the system, but that entity is missing the "field_date_time" field?

That's correct, we're using this on another site which makes a lot of customizations. They've introduced event templates, and those templates use the same event content type, just with a template boolean. We don't want dates to be stored with the template.