Upfront Builder seems to have issues in latest version

Hi. We've been using the Upfront builder now since we trialled the system. All seemed to be going well until the most recent update which we know has bugs, that we've reported.

We now seem to have issues between the desktop, tablet and mobile responsive options. Before, we could build for desktop, then edit the tablet and mobile views respectively using Upfront. We are now seeing issues where we change elements to 'tablet' or 'mobile' specific elements we create ie H1, H2 tags, centred menus etc and when saved on tablet, change the desktop. Visa versa - its as if changes either don't save, don't update or update everything. Never happened before? Its wasting countless time and is becoming a real issue. We've also saved then closed and changes get made to text, even when we haven't changed anything! Are there known issues or an update due? Thanks.