Wrapped phase plotting problem in StaMPS

Hi Forum!
I try to obtain deformation using PS-InSAR with SNAP and StaMPS. When I finished step stamps(4,4), I used command ps_plot(‘w’) to check the PS candidates. But I found that the master-master(12 Dec 2015) phase wasn’t zero. Can anybody explain why? Thank you in advance~

by the way, I’m now study in landslide, so I used ‘weed_standard_dev=1.5’ according to this Tutorial, maybe this is the reason?

Hi, I met the same problem. Did you solve it?