by Przemek Kaszubski.
Had a chance to upgrade an old 2.6.1 site, where the My Home assignment alert was working OK, to version 2.6.8 - and the alerts disappeared - as in the previous upgrade attempts. Then went ahead with the latest 2.6.10 upgrade - and the problem persists
Ergo, so far it seems that the problem ios triggered by the updates. So - if anyone cares about assignment alerts on teachers' My Home page, stick with those old 2.6 versions you have - don't go up for 2.6.8 or 2.6.10.