warnings from i.maxlik such as
WARNING: Signature 1 is not valid (singular) - ignored
WARNING: Signature 2 is not valid (ill-conditioned) - ignored
....
was coming from inappropriate imagenary group.
I added too much outputs from i.pca into target group.
It became work after removal of unnessecary image.
You can refer pca propotion file to decide whichi images are important.