Same issue on 1.13.2
exact command is /spreadplayers 8900 650 0 1 false @e[tag=ChunkLoader]
I am using it as a makeshift chunk loader for a far away location. I dont think it is due to environmental hazards due to it accepting 650 however not accepting 700, 900, 5500, 9000, 9999, or 99999
Doesn't matter. Does it Either way.
Same issue here