I find I can reproduce the OP's observations, and the most recent advice doesn't fix it (although it changes the symptoms):
>From mintty/bash: 639> cd /tmp 641> ls -ld . drwxrwxr-x+ 1 ht None 0 Dec 13 19:55 ./ 640> getfacl . # file: . # owner: ht # group: None user::rwx group::rwx other:r-x default:user::rwx default:group::r-x default:other:r-x 642> touch x3 643> ls -l x3 -rw-r--r-- 1 ht None 0 Dec 13 19:59 x3 Switch to CMD (not elevated): C:\Users\ht>cd ..\..\C64\tmp C:\C64\tmp>echo > x2 C:\C64\tmp> Back to mintty/bash: 644> ls -l x2 -rwxr-xr-x 1 ht None 13 Dec 13 20:00 x2* OK, try the advice 645> setfacl -bk . 649> getfacl . # file: . # owner: ht # group: None user::rwx group::rwx other:r-x 646> echo > y3 647> ls -l y3 -rw-r--r-- 1 ht None 1 Dec 13 20:01 y3 Over to CMD: C:\Users\ht>cd ..\..\C64\tmp C:\C64\tmp>echo > y2 C:\C64\tmp> And back to mintty/bash: 648> ls -l y2 -rwxrwx---+ 1 ht None 13 Dec 13 20:02 y2* 650> ls -ld . drwxrwxr-x 1 ht None 0 Dec 13 20:02 ./ 652> setfacl -bk y2 653> ls -l y2 -rwx------ 1 ht None 13 Dec 13 20:02 y2* Windows 10 Professional N Ver 10.0 Build 10586 3229k 2016/08/31 C:\C64\bin\cygwin1.dll Cygwin DLL version info: DLL version: 2.6.0 ht -- Henry S. Thompson, School of Informatics, University of Edinburgh 10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440 Fax: (44) 131 650-4587, e-mail: h...@inf.ed.ac.uk URL: http://www.ltg.ed.ac.uk/~ht/ [mail from me _always_ has a .sig like this -- mail without it is forged spam] -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple