The efficiency tools were nerfed in the most recent official update, 1.4.6, so that the only work on their respective block types.
However, when playing in SMP, the efficiency of tools is the same as it was before...to the client, yet the server has the nerfed tools. This means that the server doesn't actually register the block as "destroyed" until after it's supposed to be, or even not at all, and the client still believes the block is gone, causing the "invisible block" glitch that used to happen in some of the 1.4 snapshots.
Linked issues
is duplicated by 1
Comments 8
This ticket is invalid as it relates to a modded or 3rd party client/server.
Any non-standard client/server build needs to be taken up with the appropriate team, not Mojang.
Any plugin issues need to be addressed to the plugin creator.
This site is for addressing issues related to the base unmodded MineCraft.
Unable to reproduce, tried breaking glowstone with efficiency shovel, the client has nerfed tools.