Event disappearing from calendar

Environment

Discourse Version: 2.4.0.beta8 (42758379b9)

Plugin Commit: 0f2fd7f

Other Plugins
assign, data explorer, locations, solved, wikimedia auth

Steps to Reproduce

Budapest meetup (2020. január) - Events - Wikimedia Space This event is not showing up on our calendar. I made edits to the date and time to see if it would appear. Changing the date made it appear, but putting it back to January 18 made it disappear again. I then created a test event on the Jan 18 and one a few days earlier in January. When I created the test event on Jan 18, all of a sudden the Budapest meetup showed up but the test event didn’t. Then the test event showed up but the Budapest meetup didn’t, without any changes. Other dates seem to work fine. I noticed this fatal error in the logs during the time I was making changes:
NoMethodError (undefined method ’ for nil:NilClass) /var/www/discourse/plugins/discourse-events/plugin.rb:281:in block (2 levels) in activate!'

We have had similar issues with events not appearing on the map, as well as with users disappearing from the users’ map. However, I have never seen a fatal error related to the Locations plugin, only warnings.

Example

Logs

NoMethodError (undefined method []' for nil:NilClass) /var/www/discourse/plugins/discourse-events/plugin.rb:281:in block (2 levels) in activate!’