odd behaviour of `if`

Hi !

I'm getting bugged by somewhat odd (and for me unexpected) behaviour of maple:

subs(i=5,`if`(i mod 5 = 0,1,i)) = 5, but `if`(5 mod 5 = 0,1,5) = 1

and in sum and product statement the `if` behaves like with the
substitution.
What's the reason for this behaviour and is there a workaround?
In other words how can if use the `if` in formulas/products/sums ?
.

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