eshell completion: what on earth is /davs and why is it back?

i started using emacs a few months ago after a very long break.  i use eshell heavily.  i'm having a strange issue with directory completion.  i keep all my junk mounted on /data.  probably over 50% of my cd commands begin with /data, which i type as /da<tab>.  this is muscle memory i've had since 2004.  when i started using emacs a few months ago, eshell would suggest nonexistent directories /dav and /davs in addition to /data.  before i could complain, (it's hard for me to write emails like this,) it stopped.  just now, it started doing it again.

so, i have to ask, *why,* *for the love of free software,* is eshell interrupting my typing to offer spurious dirnames which have never existed on any computer i've ever owned?

copypaste, showing the dirs are really not there:

Welcome to the Emacs shell

/data/games/transport-tycoon $ ls /
bin   data  etc   initrd.img      lib    lost+found  mnt  proc  run   srv  tmp  var      vmlinuz.old
boot  dev   home  initrd.img.old  lib64  media       opt  root  sbin  sys  usr  vmlinuz  
/data/games/transport-tycoon $ cd /davs
No such directory: /davs
/data/games/transport-tycoon [1] $ cd /dav
No such directory: /dav
/data/games/transport-tycoon [1] $ cd /data
/data $