I've caused two server crashes in Resonant Rise 4 (Gravisuite 3.0.1) using the Advanced Drill in 3x3 mode. The specific behavior is that blocks with a very low durability (sometimes dirt, often Environmental Tech's Alabaster) will disappear instantly and not drop a block. The server has the block as still there, as you take damage walking through it. Placing another block back sometimes reveals the block, but then mining the revealed block can cause a crash.
Attached are two crash reports.