Software glitch?

I have had our system since last July. Starting around March of this year, about once a month, our system will go off grid for 5 minutes randomly for no reason. When it comes back on, it dumps all of our stored battery power back to the utility company. Kind of defeats the whole purpose of having battery backups. Enphase has been no help and the company that installed the system has pretty much washed their hands of it as well. Anyone else having this issue?