Line length not shown properly in cursor display box

I spaced two box sections 1000mm apart C/C, later when i went to draw a line between the two the line length read 7802198. This now happens randomly. I cannot draft anymore as the application keeps switching between the actual value and a large value. what can i do?

They are probably at differing Z values. Change to front view to see if everything is at elevation 0.

Post a drawing to remove all doubt.

Click on the line and look at "Properties" like rkent check the Z