The new engines in ksp causes the delta-V stats to just freeze an just display 0 m/s.
it seems that the engines affected are those that displays (peak) at the end of engine isp. (under more info when building). that means all the 23,5 engines and RAPIER.

I have installed a few mods so that might cause the problem.
the mods installed are. Kerbal Attachment System, ksp interstellar , EnvironmentalVisualEnhancements and Active Texture Management

This was already fixed in the dev version. Get it here http://jenkins.mumech.com/job/MechJeb2/