Server Side Repeat Expression

Either this is a bug or me being very silly.

If I set a repeat Server Side and for the expression I set 1, it repeats once, which is as expected.
If I set the expression to 0, it repeats twice.
If I set the expression to 9 - 9, it repeats three times.
if I set the expression to 12 - 12, it repeats 4 times.
So its like subtraction is working like a square root rather than a subtract.

This is just for testing, I know you would not normally set a repeat like that, but I have 2 expressions I an comparing and they both have a number output, which works perfectly until the two numbers subtract each other to equal 0, then it repeats, but should not.