Problems loading flutter web after build (in Firefox browser only)

[pro100svitlo]

Description

I am building flutter web simple app, that can play Rive animations from the assets.
Locally it works like a charm. But once I build it with flutter build web (release or debug) and than try to run it (with local host or github polished script) - it does not work and shows white screen.

It works fine in the Chromium based browsers, but does not work in Firefox.
Safari is also fine.

In the console I see next error:

From the code perspective once I remove await RiveNative.init(); - the page starts to load, but than rive animations does not show anymore.

Here I have published webpage:

• https://pro100svitlo.github.io/RivePlayer/

Here is the repo with the reproducible code

• link

I am using rive: 0.14.0

Device & Versions

fvm flutter doctor output:

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.38.5, on macOS 15.7.3 24G419 darwin-arm64, locale en-DE)
[!] Android toolchain - develop for Android devices (Android SDK version 36.0.0)
    ! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses
[✓] Xcode - develop for iOS and macOS (Xcode 26.2)
[✓] Chrome - develop for the web
[✓] Connected device (3 available)
[✓] Network resources```

[pro100svitlo]

update:

i just find out that it works fine in Chrome, but does not work in Firefox

so this issue is Firefox specific only