Slight cramping in foot arch after PF

I've been recovering from plantar fascitis in both feet over the past year and it is progressing slowley but nicely. I have done a ton of stretching exercises, many that have been listed here.

Lately I've been having an issue with "slight" cramping in the arch of both feet. It's not too painful and goes away quickly. It never occurs when I am working out. Usually late at night or even while in bed but never while sleeping.

Am I missing something in my stretching routines and/or maybe in my diet? Thanks.

RJD