Can't get initialValue working on multiple instances

I have multiple textareas on my page that I would like to use simplemde on.

I have it working like this:

const simplemde = {};

$('textarea').each(function(key, element) {
    simplemde[element.id] = new SimpleMDE({
        element: element,
        toolbar: ['bold', 'italic', 'link'],
        spellChecker: false,
        initialValue: 'TEST'
    });
});

Everything works except the initialValue which only shows on the first case on page load. But the other cases need clicking before it shows.

Any ideas?