Tossing this one out there for some else to check and see, if I'm in 3x3 mode and vein mine say nether brick, I get really weird patterns, sometimes flashing blocks, and considerable lag for a few seconds. Just for grins I pushed on even though I know I was lagging and got kicked me out of the server. Just really wanted to see if it was me or something else. 1x1 and vein miner works as normal. My dark pick works fine as well. Figured I would mention it.
