I tried what you said but without success.
In my case it was the opposite order than in usual scenario, which confused me.
I made my part of the definition inside cluster where it worked fine because cluster input performed kind of Clean Tree with Remove Empty for me (which I didn’t know about). After I received good results I saved cluster and used it outside. But performing cluster action from outside, cluster is not removing empty branches - which gave me wrong results.
To work around it, I just added Clean Tree component before cluster input.
Now when I know what exactly causes this problem I could name it correctly and search for it in the web. It’s a very old bug, discovered in 2014.
I guess I’m bumping it a bit.