brenbry on Getting 0 values in my temperature data plots

I am using an Adafruit thermocouple breakout board and a Particle Photon to transmit temperature data to a plot on my channel. However, every once in awhile, I get zero values in my plot and I do not know why. The serial output from the thermocouple does not show any 0 values. So, it must be on the ThingSpeak side. Does anyone know why this happens, or how to fix it?

Thanks!