I hope you can help me.
There's a setting in My Profile > Subscriptions menu to be notified once, then only again when you visit the thread, or EVERY time there's a new post/update, with the former being Default. I had the "once" option selected and that's why I didn't receive notif. for subsequent updates. as mentioned in my post #12 above.
There are also options there for "Site-only" notif. w/o emails, etc.
It might be good to check your Profile Subscritpion options?