Ack, not a good thing to find out right there! I shall have to adjust my brain and try remember the next time it comes up. From my (very) superficial searching, it looks like it’s still an ??accepted reading but quite uncommon.
As already pointed out, はやぐち is no longer accepted as a reading for 早口. We decided to remove it because 早口 is only read as はやぐち when it’s a proper noun, and we wanted to avoid people thinking that the vocab could be read this way. I know it’s a pain for people who have already learned the はやぐち reading and I’m sorry Rest assured that we don’t do this often — only when we feel it’s really worth it!
Thank you for that clarification. I guess, that makes sense. And sometimes you must unlearn what you had learned! ^^; Better to correct it now than never.