Unexpected behaviour with for loop

[GuthL]

Thanks for this great library. A lot of every helpful error code and well designed!
I'm reimplementing scalarMul on babyjubjub using a naive double and add approach.
When I compile my circuit with a for loop doing only one loop (for stops at 2), the circuit compile.
When I compile my circuit with a for loop doing two loops (for stops at 3), the circuit hung forever.

Stop at 2

include "babyjub.circom";
include "bitify.circom";

template babyMul(){
    signal input exp;
    signal input point[2];
    signal output mulPoint[2];

    component adder = BabyAdd();
    component n2ba = Num2Bits(253);

    var R0[2] = [0,1];
    var R1[2] = point;

    exp <= 2**253;
    exp >= 0;

    n2ba.in <== exp;

    for (var i = 1; i<2; i++) {
        if (n2ba.out[253-i] == 1){
            R0[0] ==> adder.x1;
            R0[1] ==> adder.y1;
            R1[0] ==> adder.x2;
            R1[1] ==> adder.y2;
            adder.xout --> R0[0];
            adder.yout --> R0[1];
        }
        R1[0] ==> adder.x1;
        R1[1] ==> adder.y1;
        R1[0] ==> adder.x2;
        R1[1] ==> adder.y2;

        adder.xout --> R1[0];
        adder.yout--> R1[1];
    }

    mulPoint[0] <== R0[0];
    mulPoint[1] <== R0[1];

}

component main = babyMul()

Stop at 3

include "babyjub.circom";
include "bitify.circom";

template babyMul(){
    signal input exp;
    signal input point[2];
    signal output mulPoint[2];

    component adder = BabyAdd();
    component n2ba = Num2Bits(253);

    var R0[2] = [0,1];
    var R1[2] = point;

    exp <= 2**253;
    exp >= 0;

    n2ba.in <== exp;

    for (var i = 1; i<3; i++) {
        if (n2ba.out[253-i] == 1){
            R0[0] ==> adder.x1;
            R0[1] ==> adder.y1;
            R1[0] ==> adder.x2;
            R1[1] ==> adder.y2;
            adder.xout --> R0[0];
            adder.yout --> R0[1];
        }
        R1[0] ==> adder.x1;
        R1[1] ==> adder.y1;
        R1[0] ==> adder.x2;
        R1[1] ==> adder.y2;

        adder.xout --> R1[0];
        adder.yout--> R1[1];
    }

    mulPoint[0] <== R0[0];
    mulPoint[1] <== R0[1];

}

component main = babyMul()

Have I done something wrong?
Thanks