SSA: function parameter use index 1 instead of 0

[montyly]

contract A{
    function f(int a, int b) public returns(int){
        return a+b;
    }
}

$ slither test.sol --print slithir-ssa

Function A.f(int256,int256)
    Expression: a + b
    IRs:
        TMP_0(int256) = a_1 (c)+ b_1
        RETURN TMP_0

Here `a_1` should be `a_0`. In particular this will break the taint analysis on the SSA API

[Troublor]

Can this bug be avoided temporarily by rolling back to old slither versions?