Well I found out after a while that the gizmo for the radial force is moving ahead of the actual projectile mesh, so I attached it to the particle’s root component like this:
ExplosionForce->AttachToComponent(RootComponent, FAttachmentTransformRules::SnapToTargetIncludingScale);
Now it works as expected. Not really sure why that happens, guess that’s some kind of bug.
Anyway, bug sorted. And that’s a good thing.