Spark shows offline roster after reconnecting
If Spark looses connection (e.g. logged of by another user with the same jid/resource) and then reconnects, then it shows all users offline. So one have to relogin to get correct roster.
it's fixed for me with the latest release
it is the same thing that happens when you resume from standby (other open issue)
couldn't reproduce especially this error using build 2.6.0 RC1
only recognized that spark did't load the roster properly after a reconnection (caused of connection abort)
Please review the open issues and familiarize yourself with the code.