Moving text boxes with arrow keys covers text in white space

Hello! First time posting. When editing a PDF, I often need to adjust the placement of text boxes to allow for ample spacing between subject areas. However, whenever I attempt to move both groups of text boxes or singular text boxes up or down, the text begins to become layered with white space from the background and cannot be read fully, or becomes obscured entirely. At first, I thought it was a display error, and i attempted to save the file with the obscured text and preview it. When I did this, the text was indeed still fully covered. I work with documents only utilizing text, so there's no possible image/shape layers that could be interfering.

This has become quite frustrating, and I'd like to figure out if there's any fix for this. Thanks in advance!