Lyra: OnSpawn player abilities can fail to activate on client in networked sessions

A licensee who built their game on top of Lyra has reported that OnSpawn abilities, which is a feature provided by the LyraGameplayAbility base class via its ActivationPolicy, have a chance of failing to activate the first time that a newly connected player spawns in. The issue happens rarely, is difficult to reproduce but has happened more than once on their live servers. The problem does not occur on respawns, only on the player's first spawn.

Haven't been able to reproduce in controlled environment, but any repro requires the Lyra experience to be configured with player abilities with ActivationPolicy == OnSpawn. B_TestInventoryExperience provided by Lyra is one of those.