Bug: openFeatureAPI.client.onProviderReady invoked twice or not at all, instead of once #2053

I am using the following setup:

val openFeatureAPI = OpenFeatureAPI.createIsolated()
openFeatureAPI.setProviderAndWait(flagdProvider)
openFeatureAPI.client.onProviderReady(handler)

The flagdProvider is configured to use an in-process resolver.

I expect onProviderReady to be called exactly once. However, during testing, I noticed that it is occasionally invoked twice or not at all. Why does this happen?

I have created a reproducer to demonstrate this issue.

To reproduce run:

gradle test