inconsistancy in regex

Can anyone explain this to me? Why does "GETTING STARTED" match a[^cns] until I put it into an H1? (Testing on Chrome)

        var regex = /a[^cns]/gim
        console.log("test: " + regex.test("GETTING STARTED"));
        var h = document.createElement("H1");
        h.innerText = "GETTING STARTED";
        console.log(regex.test(h.innerText));

If I change this to

    var regex = /a[^cns]/gim
    console.log("test: " + regex.test("GETTING STARTED"));
    regex.lastIndex = 0;
    var h = document.createElement("H1");
    h.innerText = "GETTING STARTED";
    console.log(regex.test(h.innerText));

It works as expected

>Solution :

Don’t use //g.test()

Using test() on a regex with the "global" flag