Cascade beam emitter lifetime module is broken.
Working as expected in 4.19 CL# 4033788
Found in 4.20 CL# 4233996, 4.20 CL# 4247867
This is a regression.
The beam particle will stay there infinitely
The beam particle would die and respawn based off the lifetime module
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-62477 in the post.