RuntimeError: dictionary changed size during iteration

[ostrolucky]

Got this

Looking for changes
Traceback (most recent call last):
  File "/usr/local/bin/unison-fsmonitor", line 312, in <module>
    main()
  File "/usr/local/bin/unison-fsmonitor", line 289, in main
    reportRecursiveChanges("", triggered_reps[replica])
  File "/usr/local/bin/unison-fsmonitor", line 239, in reportRecursiveChanges
    reportRecursiveChanges(os.path.join(local_path, path_tok), new_lvl);
  File "/usr/local/bin/unison-fsmonitor", line 239, in reportRecursiveChanges
    reportRecursiveChanges(os.path.join(local_path, path_tok), new_lvl);
  File "/usr/local/bin/unison-fsmonitor", line 239, in reportRecursiveChanges
    reportRecursiveChanges(os.path.join(local_path, path_tok), new_lvl);
  [Previous line repeated 2 more times]
  File "/usr/local/bin/unison-fsmonitor", line 238, in reportRecursiveChanges
    for path_tok, new_lvl in cur_lvl.items():
RuntimeError: dictionary changed size during iteration
Fatal error: File monitoring helper program not running

Happened after writing bunch of changes and launching unison client