Close page and show new page through mx.data.action() microflow call

I have the following piece of JavaScript in a custom widget:

            console.log('My origin is: ' +this.originPage.path);
            console.log('My origin is: ' +this.originPage);
            mx.data.action({
                params: {
                    actionname: this.mfOK,
                    applyto: 'selection',
                    guids: [this._contextObj.getGuid()],
                    origin: this.originPage
                },
                callback: function() {
                    if(this.closeForm){
                        mx.ui.back();
                    }
                }.bind(this),
                error: function(e) {
                    logger.error('Error executing microflow: ', e);
                }
            });

The output to the console of the originPage shows what I would expect: originPage.path shows SomeModule.SomePage.page.xml and originPage is [object Object].

In the this.mfOK microflow I close a page and I open a new page. The microflow executes succesfully (status 200). Furthermore, this.closeForm is false, so mx.ui.back() does not get called. However, the above call leads to an the following error in mxui.js: "An error occurred while handling queued requests: Cannot read property 'close' of undefined".

How do I call a microflow from a widget which closes the current page and shows a new page?