I get duplicates on this reproducer with plain df, i.e. without -a. Originally, the issue was reported for RHEL 8 [1] but I can reproduce it even on the latest stable release of coreutils shipped with Fedora Rawhide.
$ mkdir -p /original /bind1 /bind2 $ mount.nfs server:/nfs /original -v mount.nfs: timeout set for Fri Mar 10 10:50:59 2023 mount.nfs: trying text-based options 'vers=4.2,addr=192.168.122.40,clientaddr=192.168.122.121' $ mount --bind /original/testd1 /bind1 -v mount: /original/testd1 bound on /bind1. $ mount --bind /original/testd2 /bind2 -v mount: /original/testd2 bound on /bind2. $ df -ht nfs4 Filesystem Size Used Avail Use% Mounted on server:/nfs 97M 5.4M 92M 6% /original server:/nfs/testd1 97M 5.4M 92M 6% /bind1 server:/nfs/testd2 97M 5.4M 92M 6% /bind2 $ mount --bind /original/testd1 /bind1 -v mount: /original/testd1 bound on /bind1. $ mount --bind /original/testd2 /bind2 -v mount: /original/testd2 bound on /bind2. $ df -ht nfs4 Filesystem Size Used Avail Use% Mounted on server:/nfs 97M 5.4M 92M 6% /original server:/nfs/testd1 97M 5.4M 92M 6% /bind1 server:/nfs/testd2 97M 5.4M 92M 6% /bind2 server:/nfs/testd1 97M 5.4M 92M 6% /bind1 <- dup server:/nfs/testd2 97M 5.4M 92M 6% /bind2 <— dup [1] https://issues.redhat.com/browse/RHEL-5649