Is my device incorrectly sending ACKs on the canBus?
It looks like the CAN transceiver on the v8 board is not driving the bus and is effectively operating in receive-only / silent mode.

In the trace on the left, you can see that the dominant ACK bit that the v8 board sends on the TX pin didn't make it through to the bus and back onto the RX trace. The trace of the v7 board on the right shows the ACK bit successfully driving the bus into the dominant state.

Some possible causes to investigate:

Is the CAN transceiver in silent mode?

Some CAN transceivers have dedicated pins to disable them and place them into silent mode, others make their slew control pins do double duty for controlling silent mode by specifying a pullup/pulldown value that will disable the transmitter. Double check that the pulldowns in your design are correct and that the installed pulldowns match the design.

Is the CAN transceiver supply rail good enough?

I haven't seen this personally, but maybe the transceiver is trying to drive the bus, but isn't able to drive the lines to the correct differential level for a dominant bit because the supply rail is either too low voltage (most CAN transceivers expect a 5V rail), or because the rail can't supply enough current (100mA peak) for the dominant bit. Try scoping the CANH and CANL lines to check if transceiver is trying to drive the ACK bit and failing vs doing nothing at all.

Is the CAN transceiver broken?

Maybe you were unlucky and installed a broken part. Try swapping out the CAN transceiver with a new one and see if it helps.