x64 fixpath.exe doesn't setup correct environment to run x86 process

Uncovered weird issue with running cscript.exe from 64bit fixpath related to broken WoW64 mapping of file system paths.

Consider the following simple JS:
---
WScript.CreateObject("Scripting.FileSystemObject").GetFolder("C:\\windows\\Sysnative")
WScript.Echo('OK')
---

Run it with standalone cscript.exe, all good:
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$ /cygdrive/c/Windows/SysWOW64/cscript.exe //Nologo 'C:\Users\asemenyu\Documents\Sysnative.js'
OK
---

Run it with cscript.exe, started from 32bit fixpath, still all good:
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$ /cygdrive/c/work/as/jds/work/10/jdk10/build/windows-x86/configure-support/bin/fixpath.exe -c /cygdrive/c/Windows/SysWOW64/cscript.exe //Nologo 'C:\Users\asemenyu\Documents\Sysnative.js'
OK
---

Run it with cscript.exe, started from 64bit fixpath, all bad:
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$ /cygdrive/c/work/as/jds/work/10/jdk10/build/windows-x64/configure-support/bin/fixpath.exe -c /cygdrive/c/Windows/SysWOW64/cscript.exe //Nologo 'C:\Users\asemenyu\Documents\Sysnative.js'
C:\Users\asemenyu\Documents\Sysnative.js(1, 1) Microsoft JScript runtime error: Path not found
---

OS: Windows 7 64bit, Cygwin 32bit. Sysnative.js script attached.

My best guess of the problem is that 64bit fixpath.exe doesn't setup environment to run 32bit cscript.exe properly and mapping for virtual 'Sysnative' folder doesn't work.
This is minor issue and I have workaround for it, so this is not critical. But this looks like a time bomb and source of weird build errors.