This is just a shot in the dark, but ....... there are 2 low current spider connectors that are not part of the "normal" neutral return circuits.
These contain a separate neutral circuits, amongst others, from the ABS ECU, ECU and the dash multi function meter. Being electronics, I'd suggest that it's something like a 5 Volt neutral return.
There is also the Front Cowling Connector #3 that contains the normal spider neutral high current circuit as well as the separate low current neutral circuit.
Weird faults may happen if there is a high resistance connector on the electronic grounds.
That connector #3 is down by the S6 neutral connector and subject to corrosion.
The 2 neutral's in the front cowling harness, the normal spider high current and electronic neutrals.
I think from memory, the dash multi function meter neutral was in spider connector S5, Black / White wires, under the tank, RHS near the temperature sender.
Shouldn't take long to check and clean up the connectors.
Use some carbon grease to stop any high resistance. Dialectic grease is an insulator and shouldn't be used in this instance.
PS I'd also seat & re-seat the connectors on the ECU and ABS ECU a few times, could be high resistance on the pins there.
Wouldn't use carbon grease on those particular connectors, create a short circuit.