Question on ringtones' length

Have an i730. I noticed that some ringtones do not play out their full kb
length when a call comes in. However, the same ringtones will play out their
full kb length when "playing" them as a test thru my phone's "ringtones"
menu icon.

As a result of their not playing out to full length when they alert me to an
incoming call, I find that the call is often disconnected rather quickly
before I even have the chance to pick up the phone (if not on my belt clip).

Is this common with any ringtone?

I think what you need to do is extend your incoming rings. If so, call
customer care.