Rejecting 'index.html*' files causes recursion to include parent-directories

[Carl Ponder via Primary discussion list for GNU Wget]

I'm running wget version 1.20.3 (and earlier) using this command-line

   wget -P dir -r -nH -np --cut-dirs 3 https://svn.site.org/X/Y/Z

to retrieve the contents of the remote-directory "Z" into local 
directory "dir".
This works fine except that i also get files "index.html" in all the 
sub-directories, that I don't want.
Yeah, I know I can delete them afterward, but is there a way to just 
filter them out in the first place?
If I try this form

   wget -P dir -r -R 'index.html*' -nH -np --cut-dirs 3
   https://site.org/X/Y/Z

I find that it's downloading subdirectories from the parent levels as 
well, even though I set the -np parameter.