Fonts not rendering correctly in Firefox

Hello.
I have run into an issue where fonts are rendering in Firefox approximately 3 pixels smaller than in other browsers (Chrome, Safari and Edge), I have tested several fonts (such as Lato, Open Sans, Sriracha) and I am having the same problem with all the fonts I have tested. What's interesting is that the fonts are rendered in the correct size when opening the html page directly into Firefox. When the page goes through an HTTP server, that's when the sizing issue occurs. The font itself is displaying fine. It's just a sizing/and or letter spacing issue in Firefox when it goes through the server (again, in Chrome and Safari the page renders fine). I'm using a Java HTTP server. I tested the fonts on Apache Tomcat and Jetty in localhost. I have analysed, and compared the locally run html page and the page loaded by the Java HTTP servers using Firebug and there are no errors or warnings. The font faces are loaded correctly and their are no loading issues. The Firebug inspector and style editors are showing that the html content and styles are exactly the same between the page loaded directly and the page loaded by the servers. The Firefox version I used is 77.0.1 running on Windows 10.

Here's the test page I've been using:

[test-googlefonts-raw.txt](https://github.com/google/fonts/files/4818093/test-googlefonts-raw.txt)

Any suggestions would be appreciated? Thanks.