The PCV Valve heater is actually under the intake manifold on an N52 engine. The O2 Sensor fuse on my parents E60 kept blowing (and it had enough miles on it to make me believe that it could be a bad O2 sensor heater, so I replaced all four O2 sensors and it kept having issues.) I finally looked at the wiring diagram and that heater valve is on the circuit. The dealer did the recall, but they wouldnt change the fuse because they claimed that wasn't the issue.
I changed the fuse after the recall and I haven't had an issue since. If they changed that PCV valve, they were playing around in your engine bay and could have buggered something up.