Your title states "second MOCA bridge", but there is only one in your diagram. Is there another MOCA bridge you haven't shown?
Some initial thoughts.
•Have you assigned static IP addresses to any of your computers? If so, what IP addresses did you use?
•Your signal may be split too many times.
•What kind of coax runs do you have? Is it RG-6 (thick, stiff), or RG-59 (thin, flexible)? You may have too much high frequency signal loss if it's RG-59.
•Are all three splitters VZ supplied? If not are they rated to 1Ghz or better?
•Also interested to see the MOCA stats birdfeedr
There are 10 kinds of people in the world; those who understand binary and those who don't.