Group of newly created files with NFSv4 ACLs

[paper_oasis]

Sometimes when I create a file, it bears the same group name as its parent directory. I believe it's only when I use NFSv4 ACLs.
Any idea why this behavior happens? I'm curious if I coupl change it to standard Linux behavior without turning off NFSv4 ACLs? Or perhaps could I expand it to the file owner as well?