Fill command works improperly in a chain command block

When attempting to use a Chain Command Block with a fill command, the command fails with the error message: "[10:09:33] Too many blocks in the specified area (maximum 32768, specified 82000)". The command was "fill ~20 ~-22 ~9 ~-20 ~-3 ~12 minecraft:red_stained_glass destroy", specifying an area of only 3,200 blocks.

Here's some info on the blocks involved:

Block at -1280, 56, 1353:
Block: Oak Button

Block at -1277, 56, 1354:
Block: Command Block
Command: fill ~20 ~-20 ~1 ~-20 ~-1 ~4 minecraft:white_stained_glass replace
Facing: Up
Conditional: False

Block at -1277, 57, 1354:
Block: Chain Command Block
Command: fill ~20 ~-21 ~5 ~-20 ~-2 ~8 minecraft:pink_stained_glass destroy
Facing: Up
Conditional: False

Block at -1277, 58, 1354 (This is the block that is having issues):
Block: Chain Command Block
Command: fill ~20 ~-22 ~9 ~-20 ~-3 ~12 minecraft:red_stained_glass destroy
Facing: Up
Conditional: False

Here is a link to the world save.