WebGL simple 2D game tearing

I have made slime volleyball 2D in [unity][1]. The quality settings are set to "very low" but I set vsync count to every vblank. Application.targetframerate is set to -1, as advised [here][2]: I build for the web. The game runs smoothly for a few minutes and then tearing artifacts start to appear. Any idea why that is and how to avoid it? [1]: https://nosuchstudio.com/slime/ [2]: https://docs.unity3d.com/2019.3/Documentation/Manual/webgl-performance.html