Another hidden until you see it option is found at the beginning of any thread, left-hand side, where it says "Thread Options". The little bookmark icon will turn on/off the feature of following the thread; just in case you forgot to uncheck the following default option.

On a Mac since 1984.
Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.