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Using runtimeType here does indeed look like a bug. Thanks for finding it! I wonder why this has never caused any problems before (cc @Piinks)? Also, that this change is not failing any existing tests means we are lacking some test coverage here...

Ideally, we need a test case covering the bug that this is fixing. However, I am right now not sure how to write this one here... Maybe @Piinks has an idea?

This should either be an == check on the types or an is/is! check on the type like you've changed it to. is check is probably better, unless the intention is that we don't match subtypes?

I see a _lastNotificationType being set to a runtimeType, but that seems to be correct; it's explicitly declared with type Type?.

To be honest I don't have the time to dive into it the coming weeks. Maybe it's better if someone takes this change. I won't feel bad if this PR is closed in favor of a more complete fix.

No worries @GeertJohan, thanks for contributing and bringing this to our attention. I'll file an issue to follow up on this.

Filed #113840 for follow up. Once we can identify a case where this creates a bug, we can write test for the fix. :) Thanks @GeertJohan!