Welcome new member!

I'm not sure exactly what you are referring to when you say "attend mode". I can tell you this however. I'm not aware of any software glitch that affects CID. Caller ID on a business system is different from a residential system in this way. CID is only transmitted to ringing phones. If you are in your office and you hear the phone ringing at the reception desk CID will not appear on your personal phone unless the call is either transferred to you through the AA or someone else takes the call and transfers it to your extension.

Now as far as dropped calls, can you go into a bit more detail as far as any key pressing to try and answer the call, or is it the incoming call dropped or the original call?