Messenger now defaults to AVAILABLE on login or refresh
[ Edited ]
As of this morning (Aug. 28) the Messenger service (I use the term loosely) automatically defaults to "AVAILABLE" when logging into your mail OR when you refresh the page once logged in REGARDLESS of your settings.
Even after changing settings to show OFFLINE the ATT online email will not save the setting.
This was discussed for 40 minutes with ATT Technical Support. They eventually stated that Yahyoo! support confirmed the issue, confirmed it started this morning, and said there is no ET for a fix, just "Give us 24 to 48 hours."
So, if broadcasting you're online (in Message) is a security issue to you, be sure to RESELECT "Messenger > Sign Out Of Messenger" as soon as you open the Webmail page, then log out of your mail when you are done.
With any luck the yahoos at Yahoo! will learn how to program in the next day or two (don't hold your breath).
NOTE: condition was tested under two operating systems (Windows and Android) and four different browsers.