Marking as I have the same exact problem.

So I unplugged my Megasquirt for some length of time to try the stock ECU for troubleshooting. Then I swapped back to the Megasquirt and returned to a previous cal.

Now that it runs again, the wideband CAN box is once again not properly communicating between the ECU and the WBO2. Innovate wideband MTXL gauge indicates something that isn't full rich, while the Megasquirt CAN reading shows whatever I set the communication failure value to. I've also tried going back to previous restore points for both the Megasquirt and CAN case.

I've unplugged the WBO2 to CAN connection for shits and giggles. Both blue lights still flashing regardless.

What other settings can I check? What else can be changed?

As per usual, whenever I ask for help is when I find the answer. It seems a flaky ground related to the gauge lighting was the root of the issue. I saw some magic smoke come out which is always worrying. I adjusted some grounds and all seems to be right in the world, wideband on Tunerstudio and the gauge match.

Tangentially related question - with CAN wideband, do I need to worry about the ECU and wideband sharing a ground? Innovate seems to make a big deal about supplying clean consistent voltage to the gauge relayed direct to the battery, while many of the megasquirt specific discussions I have found emphasize powering the wideband off of the ECU, but they all seem to be about using a analog signal. Which is best for a CAN setup?