Networking issues

I have 4 Humminbird Helix graphs networked together in my boat on a 5 port Ethernet switch.
Console units are a Helix 10 MSI G3N and a Helix 10 MSI G2N. The G3N has a MSI transducer as well as a high speed 2D transducer Y cabled into it.
On my bow I have a Helix 9 G3N MDI and a Helix 12 G4N MDI units.
The helix 9 has a MDI transducer coming from the Terrova trolling motor. The Helix 12 is hooked up to 360 imagery transducer.
For the past 3 years I have been able to share through the network 2D MSD and MSI to all graphs from the G3N. I have also been able to share 360 to all the graphs from the Helix 12. That still works flawlessly.

For some reason the G2N and the helix 9 won’t read temp from the G3N but the helix 12 will.

About a month ago this started to happen. None of the graphs will read 2D from the the G3N. They will read it for a couple seconds then lock up.
Does anyone know why this is happening now all of a sudden? All graphs will share waypoints with one another and all graphs can receive the 360 signal from the Helix 12.

For some reason ever since I bought the boat new the Helix 9 connected to the terrova will read depth for a minute or so and then it looses that signal as well.
Does anyone know why this is going on?

Have you done a software update on all units lately? Don’t forget the I-Pilot Link software update too.

No I haven’t done any software updates.
I have been thinking about that as well. However I keep coming back to this question.
Why would updates fix this problem since it worked perfectly fine for the last 3 years?

I have 3 legacy units on my Pro V and I occasionally have a similar issue but mine is less than 50% of the time. In my network menu I can select from the networked temp sources from the 2 sources that I have so I always use transom temp first and then Terrova temp second, as one is always in the water and one isn’t.