DateStyle ignored in postgresql.conf during 9.5 start?

Hi,
I can set DateStyle='ISO, YMD' in postgresql.conf in PostgreSQL 9.3 and 9.4, but not in PostgreSQL 9.5. The DateStyle setting seems to be ignored during server startup, but only in 9.5. I made other changes to postgresql.conf which were applied, so it is only affecting the DateStyle setting. I am using 9.5.3-1 x64 on Windows 7 x64 and it is reproducible.
To confirm the issue, I set DateStyle in postgresql.conf in 9.3, 9.4, and 9.5 on separate machines:
#Excerpt From postgresql.confDateStyle = 'ISO, YMD'
On the machines running PostgreSQL 9.3 and 9.4, I restart, connect with psql, and execute "SHOW DateStyle". It shows the value I set in postgresql.conf:
postgres=# SHOW DateStyle; DateStyle----------- ISO, YMD(1 row)
On the machine running PostgreSQL 9.5, I restart, connect with psql, and execute "SHOW DateStyle". It shows the default value, not the value I set in postgresql.conf:
postgres=# SHOW DateStyle; DateStyle----------- ISO, MDY(1 row)

In 9.5, I am able to set DateStyle via psql and it works. So, the DateStyle value is only being ignored from postgresql.conf.
postgres=# set DateStyle='ISO, YMD';SETpostgres=# SHOW DateStyle; DateStyle----------- ISO, YMD(1 row)

In summary, the issue is PostgreSQL 9.5 ignores my DateStyle setting in postgresql.conf during startup.
Is this is a regression bug in 9.5, or a functionality change? Is there a workaround?
Thank you,Justin Cranford