turtle wondering off?

Recenctly put my server back onlne, i used to run technic pack, its been updated to include computercraft, this is first time ive used it, its quite complicated to me, not sure how to use correctly but I made a turtle and im trying to dig a hole 27x27x9.. basicly Im just saying excavate 27 and it seems to work, ill stop when it gets to deep..

I have a house next to the hole, I tend to wander in there and pop back now and again to empty the turtle of various stuff..

twice I have come back to the hole, to find the turtle not there anymore.. and ive had to make more, seeing as this new server has been online for a day now 3 diamonds is quite expensive for me as I need them for other various things so I cant keep making new turtles all the time..

Does anyone know why they are dissapearing? is this intentional? can they be found in the world somewhere else? or haev they simply disapeared?

Any help would be great thanks :P/>/>

mining turtle btw

Hi

I know of an SMP bug where a moving turtle can disappear e.g. if the chunk unloads