1) Welcome to the Party!
2) As you are obviously new here, I have some suggestions to help us all help you:
When you post, please post your entire configuration including (but not limited to) your installation method and vicidial version with build. (I see you posted some ... but all would be very useful!)
This IS a requirement for posting along with reading the stickies (at the top of each forum) and the manager's manual (available on EFLO.net, both free and paid versions)
You should also post: Asterisk version, telephony hardware (model number is helpful here), cluster information if you have one, and whether any other software is installed in the box. If your installation method is "from scratch" you must post your operating system and should also post the .iso version from which you installed your original operating system. If your installation is "Hosted" list the site name of the host.
If this is a "Cloud" or "Virtual" server, please note the technology involved along with the version of that techology (ie: VMware Server Version 2.0.2). If it is not, merely stating the Motherboard model # and CPU would be helpful.
Similar to This:
Vicibox X.X from .iso | Vicidial X.X.X-XXX Build XXXXXX-XXXX | Asterisk X.X.X | Single Server | No Digium/Sangoma Hardware | No Extra Software After Installation | Intel DG35EC | Core2Quad Q6600
3) Your system is nonstandard and you did not post a link to your installation instructions. Please post it, so any other problems with this installation method can be linked (and users like you who use it can all be warned at the same time of these challenges, thus avoiding having to go through this process many times).
4) Why did you not install your system with the standard .iso image from Vicibox.com? (Often this helps us recognize your limitations, sometimes it even helps us find your problems, occasionally before they happen, LOL).
5) Please provide some more details: When did this call actually occur? When did it end? Have you tried a control sample (with yourself on both ends of the call) to see how far off in which direction these numbers are, and how often they occur? How often does this occur? All calls? Same time differential each occurrence?
6) Is this a fresh install where this problem has been present the entire time? Or a six year old install which has been upgraded multiple times (including 5 minutes before this call was made, and this problem occurred right then)? As you can see, it is possible to provide much more information to help us narrow do the likely problems without trying to list all possible problems and hope you can wade through it all. Not to mention that listing them all would be a long task. LOL
7) One more time, for the record: Why did you not install with the Vicibox .iso image from Vicibox.
Happy Hunting!