Feeds are no longer posted in chat

Question

As far as I can tell, at some point today today chat feeds posted in various rooms stopped being posted as chat messages into rooms. What is actually the problem? Can this be fixed?

Some examples where feeds are no longer posted:

• I have created a room for testing feeds. I have included several feeds which have relatively large number of posts. Although since I started the room, there have been several new posts in the tags I have chosen. (Among other things, this very post should be caught by the feeds.)
• The Hot Network Questions has feeds to catch all HNQs. (It uses the feeds provided by rene, see: How to add HNQ to chat room feed? and How to determine if a question has ever been a “hot network question”?) They stopped being posted at some point today. (This is the most recent message in that room at the moment.)
• The 2nd Monitor has a feed of all recent questions from Code Review, the feed is called Captain Obvious and it also stopped making posts in chat today (and there have been several questions since then). The most recent message from that feed as of now is this one.

Answer 1

I merged a chat PR earlier that added a couple new checks on room properties when creating a new message. And apparently a room can be null at that point. How? Why? Nobody knows, but null reference exceptions can be quite cruel.

The checks have been corrected and feeds have resumed posting as far as I'm aware. If you're still having an issue with a feed, please comment on this answer with the details and I'll check it out.