0 miles?

Evening guys im alittle confused/concerned
As some will know I snaped my timing chain a few months back and its been sat waiting for me to get time to swap the engine.
Today I went out to check no electronic gremlins had snuck in re. the alarm ect..(Actually just got board) the battery was dead! Fortunatly it was unlocked so put some jumper cables on and turned ignition on and the noticed the mileage is at 0
Any suggestions as what might have happened? Am I gona have any sort of sync problems when I finally fit the donner engine?

Ahhh I know whats happened here, your local LandRover dealer has just honored the "If your chain snaps we will fit a brand new engine policy" I believe only a few Range Rovers where sold with these clauses........ or maybe not..

No its ok now! Had it on charge for a bit and its reading ok
Some sort of glitch? It has been dead for about 6 months