Does anyone else ever get those little lag-glitch things where you mine something (like a piece of stone) and something like moss stone or diamond or lapis ore shows up behind it and you get all excited and you mine it and its another piece of stone? -_- I've seen this happen on Factions, not sure if it happens anywhere else though. Sometimes it shows up for a split second, and sometimes long enough for me to mine it and see the disappointment. xD If someone could look into it I'd really appreciate it. I know it's not one of those simple problems that can be fixed in a few minutes.
If I'm not mistaken, I think this is block lag due to an Anti-xray plugin. I may be wrong, but I am thinking its that.
You're right, the block lag with the Anti-xray plugin makes it look like diamond might be there or something else but when the lag clears it shows the proper block, there's not really any way to fix it unless you remove the plugin entirely which I'm relatively confident, will never happen.