Why obtained values are different after run=0?

Hi, my friends!
I use “run 0” after a long process for saving my dump but the obtained values for same variables are different.
For example Pxx = -6829.2019 bars & after run=0------->Pxx = - 6835.8808 bars.

I don’t underestant that why it’s happend?

Thanks;
Nili