Issues with Rendering Variable Fonts in opentype.js 2.0.0

[MMaturax]

Current Behavior

I have encountered issues when rendering variable fonts using opentype.js master branch 2.0.0. Specifically, some characters are rendered incorrectly. These errors occur with almost every variable font I've tested, manifesting in various ways. I have taken sample screenshots directly from opentype.js to illustrate the issues. Here are two examples:

Readex Pro Font
In words containing the lowercase letter 'l', the thickness of the letter does not change regardless of the WEIGHT value. It remains at its original thickness.
Download link: https://www.cufonfonts.com/font/readex-pro

Mona-Sans Font
When changing the Slant value, the letter 'i' becomes distorted, displaying as a double line.
Download link: https://www.cufonfonts.com/font/mona-sans

These issues make it difficult to use variable fonts reliably with opentype.js. Could you please investigate and provide guidance on how to address these problems?
Thank you in advance for your assistance.

Your Environment

• Version used: 2.0.0 master-branch
• Font used: Readex Pro Font Variable, Mona-Sans Font Variable
• Browser Name and version: Chrome 127.0.6533.120
• Operating System and version (desktop or mobile): Windows 11, Desktop