It would be either red/green or blue/yellow colorblindness. Most likely red/green because it’s more common, but the latter does occur.
I happen to also have a form of colorblindness (deuteranomaly trichromacy which means I’m color “weak” rather than unable to see certain colors, for more details see the thread any color blind pilots out there?)
It’s not that particular issue that makes pilots absent-minded, just sayin’ 