RidgeCannon

Thank you both. I just had to replace the frame. IDML format must be a little trickier. 

Possibly you have resized a text frame with its outer bottom right handle which scales the frame's contents, too.
Or the frames come from an IDML where frames can carry such a confusing, hidden font size information in their upper left corner left of the first character.
In both cases the fastest fix would be to detect the affected frame and delete / replace it by a new one.

Thank you both for the assistance! Hoping this will totally replace my previous product.
 

Hi @RidgeCannon,
Welcome to the Affinity Forums!
Sounds like a baseline grid is working, could be set document wide or with a paragraph style.
By the way: one difference to your predecessor app is the interface for paragraph leading: in Affinity it gets set in the Paragraph panel, were it's placed together with space before / after and indents. What you have set in the Character panel is the Leading Override. It is meant to get applied like a character style, selectively rather than to entire paragraphs. As ist says it "overrides" the paragraph setting and thus may cause unexpected result if used as general leading interface.

You are changing the Leading Override in the Character panel. Set that to Auto & in the Paragraph panel, set the Leading in the Spacing section to whatever you want.