I can attest that the problem is most likely because you have more than 2 graphs sharing 2D transducer along with the 360.
I have the exact same issue I'm battling and it mostly began when I added a 3rd Helix to my mix.
I get the same random spokes on 360 with 2D being source of the crosstalk.
Let me explain my current setup:
Bow Helix12 SI G2N Mega sources:
2D (Helix 10 GPS)
DI (none)
SI (none or 360 doesn't affect issue)
360 (on)
Console Helix 10 SI G2N Mega sources:
2D (Helix 10 GPS)
DI (Helix 10 SI)
SI (Helix 10 SI)
360 (on)
Console Helix 10 GPS G2N sources:
2D (Helix 10 GPS)
DI (off)
SI (off)
360 (off)
While on the water yesterday, I was seeing some form of crosstalk while 2D was being pinged from the Helix 10 GPS unit (which is shared to all 3 units.)
If I turned sonar off on the Helix 10 GPS, there was zero issues with the 360 views on either unit viewing it.
The kicker is that when I just leave 2D on and use the 360, sometimes the images are clear and after awhile the spoking will reappear and disappear on its own.
Keep in mind no other unit is viewing any SI or DI since it's inevitable you will get cross-talk in this mode.
Back when I just had 2 units I would still get the occasional 360 hiccups but it has become more evident now with the 3rd unit in the mix.
I've opened a case about this with HB, but honestly don't really expect an immediate fix.
Here are some screencaps to illustrate:
2D off:
2D set to High Freq only:
(This is the most useable configuration I've found with the least amount of crosstalk.)
2D set to Med Freq only:
(Worse)
2D set to Med/High freq (Worst crosstalk)
Leaving 2D on, sometimes it will just clear up on its own then reappear at random times looking like this:
Of course it isn't always bad. These 2 images were captured earlier this month using 360 and 2D both together.
Just curious if any of you guys using Solix have these kind of problems?