watchman+fsmonitor cannot work in repository in junction of Windows

I mount a drive to a folder in C drive on Windows 10 (dir command shows it's junction). Then, I use Mercurial in a folder in the junction. If I enable fsmonitor in ~/.hgrc and e.g., use |hg up .|...

- If the drive does not have a drive letter, hg command won't return until killing watchman process (CPU usage becomes 0% at that time).
- If the dive has a driver letter, I see the following error:
> warning: Watchman unavailable: watchman command error: RootResolveError: unable to resolve root c:\foo\bar: "c:\foo\bar" resolved to "X:/bar" but we were unable to examine "c:\foo\bar" using strict case sensitive rules. Please check each component of the path and make sure that that path exactly matches the correct case of the files on your filesystem.

c:\foo is path to the junction. X:/bar is root of hg repository. So, c:\foo\bar is correct path to the hg root via junction.

Tested on Win10 (x64) October 2018 Update with watchman 4.9.4, Mercurial 4.7.2, Python 2.7.15. Both volumes are formatted with NTFS.