.....
You can check your profile settings. Notifications and email.
If you have not yet checked the option: Automatically watch topics after replying to them. (You can add all of your posted-in topics to your watchlist.). Now it is time to check it if it is what you need.
How does checking my notifications and email answer my second question?
Like I said in my post, I disabled the feature that automatically add topics I've replied to to my watchlist and that's because I don't need it.
.....
Also when you click a topic it disappears from your watchlist until its edited again. Other than that I se no reason why it wouldn't be there.
I just clicked one to test and it really disappeared.
I still don't get why topics with posts before yesterday won't show up. Maybe there's a 24 hour rule? Or maybe I've read them before? I can't remember.
What do you mean by "edited again"? It will show up again if there's a new post?