Media uploads cause WebGL game to become non-active on Firefox

Hey everyone, I have a really specific bug happening with my WebGL build on Firefox.

I have a Unity game running on WebGL and it’s connected to a web app that’s overlaid on top of the Unity canvas. The web app has a feature where you can upload different types of media. On Firefox, after uploading a media file, the Unity canvas becomes unresponsive. Then after I switch to another tab or window and come back, everything is back to normal. Even clicking on the browser console and then again on the game canvas works.

To me this suggested that the Unity canvas just loses focus after the media upload, but I’ve tried manually setting focus to the canvas from both the console and the index file, but this has no effect.

Any web developers here who might know what’s the issue?