Icons not displaying on Instagram/Facebook in-app browser

Hi,
We’re facing an issue where icon fonts (menu icons, navigation arrows, etc.) are not displaying when our site is opened via the Instagram or Facebook in-app browser. Everything works fine on Chrome, Safari, and other regular browsers.

We have tried clearing cache and regenerating CSS via WoodMart > CSS Generator.
Could this be a CORS issue or something related to how WoodMart handles icon fonts?

Can you please advise the best way to ensure icons appear correctly in in-app browsers?

Thanks in advance.