That's part of being too defensive, thats why people can't come in throwing punches, I think Mayweather has changed two things a lot since the Castillo fight.
1. He ties his opponent up faster instead of going into his shell on the ropes.
2. He is starting to counter more going backwards, and he uses his jab a lot less(which IMO is a bad thing because his jab was amazing at 130/135).