Cannot edit mobile view - dragging text boxes does not work

I'm having difficulty editing mobile view. What I want is to reorder the content for flow and consistency. However, when I drag the text box, the text doesn't move with it, just the outline. And then when I click the outline and press delete, the text disappears. I hope the images below explain what happens. This is the case for basically every section on mobile view. How do I fix this? 

I'm not sure if this is relevant but I'm designing a one-page website and adding a line of code to add section markers. I have designed a few websites with Squarespace already and this is the first time I'm experiencing something like this.