I just solved this issue for myself. It looks like isPublic on the Client Callable (now called 'Glide AJAX Enabled') script include actually need to be a function that returns a boolean rather than just a boolean. For example:

var example = Class.create();
example.prototype = Object.extendsObject(AbstractAjaxProcessor, {
	doSomethinig: function() {
		gs.info('Did something!');
	},
	isPublic: function() {
        return true;
    },
    type: 'example'
});