We cannot describe it as a bug, since the definition of a bug is an unexpected problem when execution, and since the results here are correct and expected, it is the way the code is executed.
It is better give an error message if sending box contain anything other than numbers, but what happens is that the first numbers are executed and the following values are ignored.
Seems like it just ignores everything that isn't a number, which feels like the ideal behavior.
I think it ignores anything after the number if it is not a number, since 1~.0 is 1, not 10, and so on.