Slide will not always advance per triggers and variables - just sometimes

I have these slides in a module for my 6th grade students. When dragging and dropping, I thought I had the variables tied to the drop text and drop sites changing to true and when all changed to true, it was to advance. However, it is only working part of the time. Did I make a mistake? I will want to do something similar in the future so want to find out the best way (without making this a formal question - unless I can get the correct answer to automatically advance to the next slide). Thank you.