This is not a regression.
//UE5/Main CL18218925 Binary - Crashed
//UE5/Release-5.0 CL16682836 Binary - Crashed
//UE4/Release-4.27 CL Binary - Crashed
Having a level open that contains an Actor with an Actor Sequence Component results in a crash with memory leaks when attempting to create a level.
I was able to get the crash every time with just an Actor with the Sequence, but user are reporting that adding a Transform Track then a Relative Transform section and keying some points increases the likely hood of a crash.
A new level is created and loaded in the view port
The Editor crashes with "World Memory Leaks: 2 leaks objects and packages"
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-138424 in the post.