Downloading themedata fails (local web)

[zacps]

Uncaught (in promise) Error: Assertion failed: org-dartlang-sdk:///dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/types.dart:94:10
_isJsObject(f) || !JS('bool', '# instanceof #.Function', f, global_)
"Dart function requires `allowInterop` to be passed to JavaScript."
    at Object.throw_ [as throw] (errors.dart:196)
    at Object.assertFailed (errors.dart:26)
    at Object.assertInterop (types.dart:94)
    at exportTheme (main.dart:59)
    at exportTheme.next (<anonymous>)
    at runBody (async_patch.dart:86)
    at Object._async [as async] (async_patch.dart:125)
    at web_theme_service.WebThemeService.new.exportTheme (main.dart:57)
    at web_theme_service.WebThemeService.new.exportTheme (web_theme_service.dart:55)
    at theme_model.ThemeModel.new.exportTheme (theme_model.dart:103)
    at editor_topbar_web.WebPanacheEditorTopbar.new.saveTheme (editor_topbar_web.dart:71)
    at _InkResponseState.new.[_handleTap] (ink_well.dart:705)
    at ink_well.dart:788
    at tap.TapGestureRecognizer.new.invokeCallback (recognizer.dart:182)
    at tap.TapGestureRecognizer.new.handleTapUp (tap.dart:486)
    at tap.TapGestureRecognizer.new.[_checkUp] (tap.dart:264)
    at tap.TapGestureRecognizer.new.handlePrimaryPointer (tap.dart:199)
    at tap.TapGestureRecognizer.new.handleEvent (recognizer.dart:470)
    at pointer_router.PointerRouter.new.[_dispatch] (pointer_router.dart:76)
    at pointer_router.dart:117
    at LinkedMap.new.forEach (linked_hash_map.dart:23)
    at pointer_router.PointerRouter.new.[_dispatchEventToRoutes] (pointer_router.dart:115)
    at pointer_router.PointerRouter.new.route (pointer_router.dart:101)
    at binding$5.WidgetsFlutterBinding.new.handleEvent (binding.dart:218)
    at binding$5.WidgetsFlutterBinding.new.dispatchEvent (binding.dart:198)
    at binding$5.WidgetsFlutterBinding.new.[_handlePointerEvent] (binding.dart:156)
    at binding$5.WidgetsFlutterBinding.new.[_flushPointerEventQueue] (binding.dart:102)
    at binding$5.WidgetsFlutterBinding.new.[_handlePointerDataPacket] (binding.dart:86)
    at _engine.PointerBinding.__.[_onPointerData] (pointer_binding.dart:129)
    at pointer_binding.dart:465
    at pointer_binding.dart:430
    at HTMLElement.<anonymous> (pointer_binding.dart:195)

[shptecheu]

Wondering if anyone found a solution to this...