Center blade no cutting as well as other blade

"I have a Snapper zt18440kh-509100 ztr mower. My center blade does cut as well as the others. I leave a small "mohawk" in grass when i mow. I have taken it to a repair shop and they said the only thing they saw was my blade bearing was going out. The problem is that this all started after I got stuck in the mud and I pulled the mower out with my truck but I didn't release the pressure on the hydro's to let the wheels spin freely. I changed the blades the next time i used it and when I putting on the new blade I noticed that the blades were able to be spun by hand where as before they were locked and you could NOT spin them at all unless the mowers on and the pto engaged. So Im trying to figure out what part I messed up for the blades not to be locked when the mowers off and if that caused my center blade to not cut as well or if that was coincidence.

Help on either problem is greatly appreciated!!!!!