Running Uglify twice results in correct optimization!

a.js

export default function() { console.log( "A" ) }

b.js

export { b }

function b() { console.log( "B" ) }

bundle.once.js

! function() {
    "use strict";

    function o() {
        console.log("B")
    }
    for (var n = 0, c = 1, t = function() {
            console.log("A")
        }, f = 0; f < 2; ++f) n && t(), c && o()
}();

bundle.twice.js

! function() {
    "use strict";
    for (var o = 0; o < 2; ++o) console.log("B")
}();

configuration.js

export const A=0, B=1;

main.js

import * as conf from "./configuration";
import a from "./a";
import * as b from "./b" ;

function foo() {

	if( conf.A )
		a();

	if( conf.B )
		b.b();
}

for( var i=0; i<2; ++i )
	foo();

rollup.config.js

import uglify from 'rollup-plugin-uglify';
import buble from 'rollup-plugin-buble';

export default {
	entry: 'main.js',
	format: 'iife',
	exports: "none",
	interop: false,
	plugins: [ buble(), uglify() /* , uglify() -- uncomment for right result */ ],
	dest: 'bundle.once.js' /* change to bundle.twice.js when uncommenting 2nd uglify instance */
};