Hi Sohel,
I guess this shouldn't be related with DST. It smells like bug which was documented in 1892328 or 1931911 (offset here looks like its -6 hours which is GMT; so time is changed to GMT). However nothing seems to match exactly with this behavior.
Improvising:
You can check Java timezone and change Duser.timezone similar to the server timezone.
Also, check what is time zone for web servers and change it to CST.
Hope this helps.
Regards,
Onkar