Just a formal question: Is that issue automatically included to bugfix list or tracked in future, if confirmed by other user as here?
No, as Tomasz already wrote. In case of your example I think the issue was the false/bad annotation. After running the “Annotate” tool the multichannel tool worked fine on your example. I took the freedom to report it (including your example) on gitlab: copy paste subsheets - something wrong with references (#20173) · Issues · KiCad / KiCad Source Code / kicad · GitLab
@dohny :
I cannot upload the project (I’m new).
If you read and follow this FAQ article you can promote yourself from “new forum user” to “basic forum user”: New Member Information
Then you are allowed to attach a example project archive. Without the project it’s impossible to give a good advice.