Cygwin making files inaccessible?

[Jay K]

Cygwin making files inaccessible?
i.e. when Cygwin copies or writes to them, not random files.

C:\t>dir /s/b/a

C:\t>dir /q .

02/05/2022  04:11 AM    <DIR>          BUILTIN\Administrators .
02/05/2022  04:11 AM    <DIR>          NT SERVICE\TrustedInsta..

C:\t>cacls .
C:\t Everyone:(OI)(CI)F

C:\t>echo > 1.txt

C:\t>cacls 1.txt
C:\t\1.txt Everyone:F

C:\t>copy 1.txt 2.txt
        1 file(s) copied.

C:\t>cacls 2.txt
C:\t\2.txt Everyone:F

C:\t>del 2.txt

C:\t>uname -a
CYGWIN_NT-10.0-WOW DESKTOP-BCFUMJ4 3.3.4(0.341/5/3) 2022-01-31 19:31 i686 Cygwin

C:\t>cp 1.txt 2.txt

C:\t>which cp
/usr/bin/cp

C:\t>cacls 2.txt
C:\t\2.txt NULL SID:(DENY)(special access:)
                    READ_CONTROL

           DESKTOP-BCFUMJ4\jay:(DENY)(special access:)
                               FILE_READ_DATA
                               FILE_READ_EA
                               FILE_EXECUTE

           DESKTOP-BCFUMJ4\jay:(special access:)
                               STANDARD_RIGHTS_ALL
                               DELETE
                               READ_CONTROL
                               WRITE_DAC
                               WRITE_OWNER
                               SYNCHRONIZE
                               STANDARD_RIGHTS_REQUIRED
                               FILE_READ_ATTRIBUTES
                               FILE_WRITE_ATTRIBUTES

           DESKTOP-BCFUMJ4\None:R
           Everyone:R


C:\t>more 1.txt
ECHO is on.

C:\t>more 2.txt
Cannot access file C:\t\2.txt

Same behavior from cygwin64.

C:\t>\cygwin64\bin\uname -a
CYGWIN_NT-10.0 DESKTOP-BCFUMJ4 3.3.3(0.341/5/3) 2021-12-03 16:35 x86_64 Cygwin

Huh?

I would hope Cygwin could/would just copy the ACLs asis.
I am guessing there is some failed attempt to translate them
to an internal form and then back to NT form.

My real scenario was open/write/read, not cp.exe.

 - Jay