Yeah, there appears to be a glitch with the "De-spawning" on the server, i've been digging alot of dirt recently to get my excavation level up.. and I got a full invent after a while of digging but I decided to carry on digging because I was looking to get levels.. not dirt, so I continued going leaving a stream of dirt behind me as I believed that it would de-spawn, after about an hour or so I got bored and teleported back to my base, I then went offline, I came back the next day and wanted to level up my excavation more so I visited the spot in which I was digging the day before to find piles upon piles of dirt, the dirt CANNOT be picked up and CANNOT be burnt using fire/lava (so its obviously bugged) it also lags out that chunk ALOT, but it was not done by me intentionally, it was a bug that caused these problems.
TL:DR Just read the damn paragraph, its not hard.