Flatiron Theme 7.0 Product Description Font Defaulting

So I have a record label site that has two store pages on it. One main store has the product descriptions set to Futura PT. It's all set up in the Site Styles. The other store has the same font in the product headings and descriptions but now as I started to add new listings and edit older listings, the product descriptions default to the font FF-Tisa which isn't even on the product description styles. Tisa is used on new articles and other parts but not on product descriptions. It's set to Futura PT. Any idea why this is happening and how I can get my product description to stick to the set style of Futura PT? I attached two screenshots of two CDs showing the font I want (Murder Bay image) and the font descriptions default to (Rattleshake image).

I don't know if your site is 7.1 or 7.0. This is the procedure for product descripton fonts. 

Colors and fonts on the Products Page and product details page follow your site-wide font and color tweaks. You can also change the color of specific store sections in the section style editor. Product details pages follow the store section's color theme.

1. In the Home Menu, click Design, then click Fonts.
2. Choose a font, and click the  to apply the font to specific parts of your site.

Use these tweaks to change fonts on your Store Page and product details pages:

Thanks for the info but there is no Fonts on the Home Menu--->Design. It's just like this image of the Home Menu. Site Styles has the fonts. It's Flatiron theme on Squarespace 7.0.

I should have read he the title of your post a bit closer,  You said Flatiron, well, that is a bit differert procedure. 

Products Page vs. product details page

Before styling your products, it's good to understand how Squarespace structures them on all sites. Products are organized in two parts: Products Pages (called Store Pages in version 7.1), which create a browsable landing page, and then individual product details pages. These areas share some style tweaks and have their own style options. To learn more, visit Adding products to your store.

Open the style options

to style Products Pages:

Made sure I was following those steps and had a look. Everything on products/individual products is set how it should be... A Heading of Futura PT and Text as Futura PT for the product listings. It's just that after Saving it that way and resaving it that way. It still defaults to FF-Tisa. And then if I go to edit older listed products, instead of staying the Futura PT as set, even those product details will go straight to the FF-Tisa font when I haven't set it that way on the product pages/individual descriptions. it driving me insane. lol

Sounds like a bug for sure. I wil do some checking on it. One question. Are you using any custom fonts?  FF-Tisa is a Serbian Font, and is not a default font at all. 

I don't think it's a custom font. I don't see anything added to the Custom CSS window. The Chrome extension WhatFont names it as FF Tisa Web Pro. But that is only used on the blog/news posts. The product listings should all be various Futura PT styles. Even when I am on a product page's site styles, the fonts are set to Futura PT but the description of the product changes to FF Tisa while the heading of the products stays Futura PT how I want it. It's just the product description being the problem. It also could be my own user error not seeing something that is obvious.

UPDATE:  Actually, I double checked. FF Tisa, Futura PT, Futura PT Condensed are Adobe Typekit fonts that were added... apparently. You were correct. Those are not Squarespace fonts.

UPDATE 2: I think I got it for now. The previous designer had injected some custom CSS into the body of the main site so it was defaulting to that FF Tisa font. Regardless of that, Thanks for your help.