crashes on bashrc reload

[ThorX89]

With the following .bashrc:

 [ -z "$bx_has__bashrc" ] || return
 bx_has__bashrc=1
 echo >&2 '. BASHRC'
 bind -x $'"\C-e": bx_bashrc_edit;'

 bx_bashrc_edit()
 {
 #set -x
 vim +'set ft=sh' "$HOME/.bashrc" && unset -v bx_has__bashrc && builtin . "$HOME/.bashrc";
 #set +x
  }

I get
 Sorry, command-not-found has crashed! Please file a bug report at:
 https://bugs.launchpad.net/command-not-found/+filebug
 Please include the following information with the report:

 command-not-found version: 0.3
 Python version: 3.4.3 final 0
 Distributor ID: LinuxMint
 Description: Linux Mint 17.3 Rosa
 Release: 17.3
 Codename: rosa
 Exception information:

 'utf-8' codec can't encode character '\udccf' in position 0: surrogates not allowed
 Traceback (most recent call last):
   File "/usr/lib/python3/dist-packages/CommandNotFound/util.py", line 24, in crash_guard
  callback()
   File "/usr/lib/command-not-found", line 90, in main
  if not cnf.advise(args[0], options.ignore_installed) and not options.no_failure_msg:
   File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 265, in advise
  packages = self.getPackages(command)
   File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 157, in getPackages
  result.update([(pkg, db.component) for pkg in db.lookup(command)])
   File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 85, in lookup
  result = self.db.lookup(command)
   File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 41, in lookup
  key = key.encode('utf-8')
 UnicodeEncodeError: 'utf-8' codec can't encode character '\udccf' in position 0: surrogates not allowed

whenever .bashrc is reloaded with Ctrl-E. Uncommenting the set `set -x` and `set +x` cause the
error text to no longer appear.