It seems normally when chiseling, it gives you bits bit-by-bit to accurately give you the right amount of each bit, but if your inventory is full while chiseling a large area with the smart chisel, they all drop out of your inventory, which is capable of crashing the game in high amounts. I don't know if they all dropped as single-item stacks or 64-item stacks since the game didn't save after crashing, but regardless it crashed the game.
Maybe the smart chisel should check if you have empty slots or existing bit stacks before continuing with the chisel process?
: I was converting 6 or 8 deepslate blocks into bits, but I didn't realize I didn't have inventory space.