I too would incline towards an electrical problem for the simple reason that it is less likely to trigger the malfunction/emissions light. Seeing that you are in Florida, my first thought was that the bike would be mainly dry but then thought that it could be subject to high humidity.
In the UK’s damp and salty environment, faults often originate in corroded connectors. Faults disappear as the multimeter is applied, because separating and rejoining connectors cleans the contacts. It is just something with which we must live. It is considered to be good practice to rejoin with silicone grease in the connector.
However, do consider the fuel. Has the bike been unused because of covid restrictions? Ethanol is hygroscopic. It may run well with the rich cold start setting, then misfire when warm and going into the normal lean burn mode.
