Are you being consistent with your nutrition?
Are you sneaking extra bites here and there?
How accurate are you with your tracking?
Are you skipping the food scale and just "eye balling" portion sizes?
You're doing too much cardio can be another reason.
When it comes to cardio, it's quality over quantity. Remember, you can only do so much. If you start with hours of daily cardio how many hours do you expect to be doing at the end of your training period?
If those reasons don't make sense to you maybe this one will. You never stop dieting. You lose 10 lbs, gain it back. ...