Unfortunately my s2r with 8000 miles had to sit outside for a couple of days when it got hit by summer thunder showers. When I cranked the bike up and got going I noticed the oil light had a very faint glow. You couldn't see it if the light hit it directly, then it went away. I figured water. It happened again the next day and went away. The day after and another rain storm and the light is full on red now. The bike is full with oil and within the service interval. The screen was cleaned and ok at the last oil change. The engine starts up and temps were never out of range. I've replaced the oil sensor once with the sometimes used NAPA part. Is my first step to check oil pressure with a gauge to determine if the problem is electrical or mechanical?
Remove the boot from the oil pressure sender and dry it out first. Pretty common issue.
Mine comes on sometimes when riding in the white rain of doom.
After you dry the connection pack with dielectric grease.