Ok let's work through this logically...
1. Is your nmea2000 terminated correctly? The nmea2000 requires a resistor at each end. So TERM-----T------T-----TERM with devices coming off each T The TERM is a resistor pack in a bnc housing. Only need two, one on each end.
2. Do you have the GFS10 units connected to an always on power supply?
3. Do you leave your charplotter plugged in or do you remove it?
I am by no means an expert, but I can figure out the logic side of things. Let's see where we get to...