The Blueprint_Effect_Explosion Actor's Root Component in the Starter Content is in some form of invalid state. It reports to have a scale of (1.0, 1.0, 1.0) in the details panel but further behaviour suggests this might not be true.
Spawning the Blueprint Effect Explosion Actor with the Spawn Actor node using the default Transform Scale Method of Multiply Scale With Root Component Scale will cause the Actor to be spawned in much higher (in the Z axis) than expected.
Changing this to Override Root Component Scale (and providing a scale of (1.0, 1.0, 1.0)) causes the Actor to be spawned where we expect.
Another solution to this bug is setting another component in the effect Actor as the Root Component, then setting P_Explosion back to being the Root Component. Even without any defaults changed this seems to resolve the invalid state and the effect Actor can now be spawned with the default values of the Spawn Actor node without issue.
Hayden Simpson 2023-09-22 06:11:49 UTC
Bug report for case [https://udn.unrealengine.com/s/case/5004z00001snfMMAAY/spawning-starter-content-effects-issue|00627704]
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-196245 in the post.