I’m having the same issue in UE 5.4.3 and no warnings or errors in the logs. You can also reproduce the issue with a right click → reload.
- Switch Loop Bheavior to Multiple with a Loop Count of 1 did not fix.
- Change lifespan did not fix.
- Set Bake Rapid Iteration Parameters on False did not fix.
I did other tests and on my side it’s as if it doesn’t manage all the array parameters until I open it.