iPhone contacts bar with letters doesn't work for letters D-Y? I have this very strange issue with my iPhone 4's (iOS 5.0.1 9A405) Contacts app.

As you know, there is this "bar" on the right which allows you to touch a letter and have the table directly "jump" to that letter:



On my iPhone, the bar only works for letters A, B, C, and Z. Not the letters in between. If I touch any of the letters D-Y, it jumps to C. Huh? Note that searching for a contact starting with letters D-Y and/or scrolling to it manually works fine.

While investigating for the possible cause of this weird behavior, I also found out that there's a section # between the letters C and D, which I suspect might be causing the problem. Why is it there? All contacts in that section start with C and should thus be in the C section. Here are two screenshots of the misplaced # section:





Thanks a lot for your help!
I finally fixed this by removing/renaming all the contacts in the misplaced '#' section.

No idea why it happened in the first place...