I have a strategy that's supposed to trade only once per day with set exit time everyday, 

when changing exit time for backtesting purposes I noticed that the number of trades increases: 

12:00 exit time: 188 total trades 
13:00 exit time: 208 total trades

looked at the orders logs but I can't find any day where it executed multiple trades on the same day.

any thoughts as why would this happen ?