After upgrading from rhel 6.9 to rhel 6.10, files in a cifs share can't be read

Issue

In a Linux system 2.6.32-696.20.1.el6.x86_64 and mounted (rw) CIFS share from windows server 2012 , we can access files without problems:

# cat /proc/mounts
[...]
//Windows_server/test_share/ //testshare cifs rw,relatime,sec=ntlm,cache=loose,unc=\134\134Windows_server\134test_share,username=share,uid=0,noforceuid,gid=0,noforcegid,addr=X.X.X.134,file_mode=0755,dir_mode=0755,nounix,serverino,rsize=61440,wsize=65536,echo_interval=60,actimeo=1 0 0

$ls -la /testshare_cifs/test.pdf
-rwxr-xr-x 1 root root 219809 Sep  1 19:09 test.pdf

But after upgrading CIFS client to Linux 2.6.32-754.3.5.el6.x86_64, when we try
to access the file, we get "Permission denied":

$ls -la /testshare_cifs/test.pdf
ls: cannot read symbolic link test.pdf: Permission denied
l---------. 1 root root 219809 Sep  1 19:09 test.pdf

On windows server, deduplication is on.