The selection switch is working because you can go into the mode screen. The actual connectors between the switch and the dash (including near the tank) seem unlikely to be a problem, given their construction, and given that you said you had only disconnected the battery.
That leaves the dash itself, I think. It could be you have a marginal electrical problem in it (maybe associated with condensation) that is showing up. I think I had the same failure on my Griso a single time, long before I coated the dash's PCB. At the time, I "cured" the problem by disconnecting the battery and waiting overnight.
Even though you just had the battery disconnected, you might try the overnight disconnection trick. It could be a transient problem that will go away. I can't think of anything else to try, short of taking the PCB out of the dash and down to a phone repair shop for cleaning and coating, which I recommend.
I suppose if you think the dash could be wet right now due to condensation, you could try to dry it out by making sure the bike is in a dry environment and then just waiting. It is possible a droplet of water has condensed from the air and is bridging two circuits. The dash gets wet when the temperature goes down if there has been moisture in the air.