Silver - odd firing result

I had some interesting results from trying to post fire reduce some silver bearing pots. I've done this several times before using silver in the glaze with titanium, and the results typically look like this, and are fairly permanent.


This time, the pots came out looking like this below, and the silver seemed to come to the surface of the glaze and just wipe off. 




Final Result after applying a little elbow grease.