Wanting to large of numbers for certain commands

When I tried to do "/spreadplayers 1 1 6 6 true @a" in a command block it always says for this type of command "The number you have entered (6.0) is too small, it must be at least 7.0". I am pretty sure that is a bug because I got the same output here -> "The number you have entered (100.0) is too small, it must be at least 101.0" when putting in "spreadplayers 1 1 100 100 true @a"