PostgreSQL COPY TO doesn’t honor Linux group privileges I have issues executing COPY to command, receiving below error msg:

ERROR:  could not open file &quot;/home/pgsql/TMP/out.txt&quot; for writing:
Permission denied


Postgres engine is being run as postgres user
Postgres user belongs to app group
TMP folder has below privileges set:

drwxrws---  2 pgsql app       23 Mar 28 19:47 TMP

I don’t understand why it doesn’t work.
I did quick check login as postgres user and creating file and this worked:
sudo -i -u postgres

If I change privileges to 777 all works as expected (I can do copy to command with no issues)
So as to me it looks postgres doesn’t somehow honor Linux groups rights
Can someone guide me how to resolve that (777 is not an option to me)
Server reboot helped. Privileges are treated as expected
(Not sure if only DB engine is enough to fix that thought - I had to reboot entire machine)
Thanks @Colin for tip