It might be creating the pool of cues - this was certainly an issue in the past. This happens if you don’t specify the cue path, for example in DefaultGame.ini
[/Script/GameplayAbilities.AbilitySystemGlobals]
+GameplayCueNotifyPaths="/Game/MyProject/My/Folder/With/All/My/Cues"
This will search all folders below for cue objects to instance when the cue manager is created (on launch). You should be seeing a warning in your log stating that no cue path has been specified and it’s searching your whole project. I believe you can get additional control over which cues are loaded and when using cue sets.