I am not the best person to look at your chart for you but I completely see what you are saying, I would be confused by that too because I don't see why it would say you did not O on the 14th... It looks like it coulc be either to me also!
Just curious though, what detection method do you have on yours? Someone on a different website for charting suggested to me try switch from advanced method to the FAM method... I'd just be curious if that made a difference what it says on yours then. I am not the best person to explain exactly how the FAM method works but on FF it will explain.
Anyway, good luck because it sounds like you timed your BD good for either date!