This is the natural language parsing feature.

Natural language parsing is where as you type things like Coffee at 6AM on Friday at Donut Shop, Informant changes the event title to Coffee, and the time and date to 6AM on Friday, then puts the location at Donut Shop to help create the details of your event quickly.

To turn this off, tap the menu bars at the top right of your main calendar view and choose Settings>Application>uncheck the box at 'Use NLP'