Board Thread:Support Requests - Community Management/@comment-45117243-20200416101002/@comment-9605025-20200416175846

Anons not getting notifications and not being able to edit their own posts makes sense. Without an account, the only way MediaWiki can keep track of contributions is by IP. However, having the same IP doesn't mean you are the same user. Allowing anons to edit "their own" posts opens the door for a different user using the same IP to edit someone else's post. As for notifications, a similar issue in the sense that you could be notifying a different user and/or that this different user will dismiss the notice and the actual user will never get it anyways.

As for registered users not getting notifications about anon replies, that has not always been the case. I am not sure why they made the change but perhaps because a decent amount of spam comes from anons. Fandom may have thought they were helping registered users by omitted what they thought were likely to be spam posts; although this assumption would be false. As Tupka217 said, thread-based discussions are being retired so Fandom is almost guaranteed not to make any changes/fixes to it at this point. As for their replacements, only registered users can use them. So anons posting things in discussions will be a thing of the past.