Inside the loop, if you use the function the_date() to display the date the post was published, you may run into trouble. Specifically, if there are two posts published on the same day, the second one will return nothing for a date.
To fix this, use the_time() instead. There is quirk though, as the_time() ouputs, by default, literally a time like "6:02 pm". You can pass date parameters into it though, and make it output a date instead like the_time(m/d/Y). This means that the date formatting is controlled by your theme though, instead of the Admin area. To get the control back, use this instead: