Expected: The delegate is fired on the client.
Actual: When using Iris with AbilitySystem.Fix.ReplicateTagCountContainerWithIris enabled, the GameplayTagEventMap is cleared on the client, so no delegate is fired.
See linked EPS case for detailed repro steps and repro project.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-381939 in the post.