Unknown calls after upgrade to 5.0.2

[UlfSwe]

I keep all my contacts locally on my phone. I store all my numbers with the international identifier, +468580xxx or +31346xxx, since I travel a lot. Up until now the phone can match the incoming calls to my contacts and give me the name of the caller. After the upgrade to 5.0.2 all incoming calls are shown as "unknown". If I connect my phone in my car, the car can still identify the caller. Have anyone experience the same? HTC support can't resolve the issue. Do you know how to down grade to 4? My phone is kind of useless in my daily work.