I am running Spark v2.5.8 and OpenFire v3.4.0.
If a spark client unexpectedly disconnects from the server, spark automatically attempts to log back in. The reason is usually expected for some reason – switching IP, etc.
It appears that it successfully reconnects, but it shows all friends as being offline.
The only way to fix it is to manually log out and log back in.
If there is any way I can provide more information, please let me know.