I’m more interested in how you made them appear! Yours is the only indication I’ve found anywhere that setting up Twitter in Online Accounts actually achieves anything at all. (Online accounts - Twitter)
I was wondering if I’ve just managed to miss the notifications but the GNOME 3 notification thingy at the bottom is supposed to let you view notifications that you’ve missed, isn’t it? Are the notifications you see available to look at later if you don’t acknowledge them when they appear?
The notifications appear for a couple seconds, but they are not available to see later AFAIK.
BTW, I solved my issue. I deleted my Twitter from online accounts and also revoked permission on Twitter’s website. Then I rebooted my PC. Upon rebooting the Twitter notifications stopped.