The /fill command simply ignores the max_block_modifications game rule if the command performs enough block modifications. For example, run the following commands:
/forceload add 0 0
/tp 131000 100 131000
/fill 0 100 0 131000 100 131000 stoneInstead of the command failing with the usual “Too many blocks in the specified area”, it tries to fill the blocks, freezing the server due to the incredibly large amount of chunks being loaded and filled. Even with the game rule set to the maximum (2 billion), this command should not complete, as it tries filling over 17 billion blocks.
Environment
Java: OpenJDK 64-Bit Server VM 25.0.1_p8-r1 (build 25.0.1+8, mixed mode, sharing) 2025-10-21
Can confirm as of 26.1-snapshot-6