@dinesh_b_kumar_ Being the type who doesn't make assumptions, can you provide the exact rule you used? I'm asking just because everyone approaches problems differently, and this may feel like a super-simple approach. The Regex I would start off using, based on what you stated in your question would be.
I escaped the colons simply out of caution, but I would expect this to work.
The only other thing I would validate is the format of the first field in your classification. If it's text, you should be fine. If you are still having issues, I also agree you should be contacting Customer Care to determine the technical problem. Best of luck!
Based on your 2 sample strings, I'd say your regex pattern may not be accounting for the "-" character.
If you've verified the correctness of your Classification rules with the "Test rule set", then you might want to bring this up with Client Care to see if there is an unknown bug that's causing your issue.