This looks like an inset that is applied in Text Frame Options. It could be that you have a default object style that contains the inset, so it is being applied to every text box you create.
I think an inset line only shows when the frame is selected, so it looks like Amanda's text frame is simply not aligned to the margin and needs to be selected and moved?
Thank you for helping me to realize that it was in fact a text frame. I inherited a template from the person who last did my job, and when I tried to correct the margins (which I noticed after I had already typeset a few articles), the text box didn't adjust automatically. I am brand-new to InDesign and not familiar with all the menus so I am not sure if there is an option where I can automatically fix it? I ended up going through and manually adjusting the box on each page by hand, which threw off the tables and charts and took me much longer than expected. Is there a quicker way to do this? Thank you for helping me out!
You can try checking Enable Layout Adjustment when you change the page margins, but that will only adjust frames that are aligned with the margins:
There are also Primary Text Frames, which lets you include a primary text frame on the master pages—primary text frames are designed for layout like yours.
If you set up a document with Primary Text Frame checked, text frames for the text flow will be included on the master spread set to the margins. In that case you would be able to change both the margins and the primary text frame's position from the master pages.