I had to put 1.7.9 in the Affects Versions, because it wouldn't accept 1.7.2, sorry for any inconvenience. Furthermore, this issue has not yet been reported after searching, so I can only assume Mojang are not aware.
On 1.7.2, occasionally the server will have issues with certain blocks. This appears to be when there is minor server lag. I was using WorldEdit to create different things on the server. So far, it seemed that Cobblestone and Stone both changed textures. At one point, Stone appeared to be Diamond Ore. On breaking the block, it dropped its actual item, Stone. After removing WorldEdit, my brother was "strip" mining, when he came across what he thought was diamonds. When he broke it, it dropped stone. This is highly frustrating for visitors on the server, and me as the Server Owner.
From what I've seen, I think it might be server lag which is causing it. Finally, I do realize that 1.7.9 has come out, but I cannot update as my plugins are still in 1.7.2, some are even still in 1.6!
Its obvious that the server is Bukkit/Spigot due to the amount of plugins, which sadly, makes this ticket invalid, as it relates to a modded server.