Server: Ubuntu Linux 64bit, (I don't know the exact Java version since I have no shell account on the server)
Client: Windows 7 64bit, Java 1.7
I'm playing on a multiplayer server in survival mode.
Sometimes (I could not figure out what triggers this bug), I can place blocks but cannot break solid blocks. I can break non-solid ones like torches and flower pots.
In this state, other players cannot see my avatar but can see the blocks I place. They can break the blocks placed by me.
Of course, I fully understand this is "survival" mode and I'm far from the spawn point.
The only solution is reconnecting to the server.
This has happened to other players, too.