Can't schedule a post on the same day

Hi, just updated to 5.0.19
I can schedule posts but not in the same day ?

Ex:
Current date/time = Aug 8th,2015 - 9h00am
Publish date/time = Aug 8th,2015 - 10h00am
The post is published

Ex:
Current date/time = Aug 8th,2015 - 9h00am
Publish date/time = Aug 9th,2015 - 10h00am
The post is scheduled

This makes testing a bit long ;-)

EDIT:
In further testing, I noticed the scheduler works the same day but seems to require a good few hours to be set to scheduled ? Is there a minimum time difference requirement ?

I setup a test environment and shared your access codes bellow

Thanks
Danny