i suppose watchOS 6 should either lockout apple pay if wrist detection is turned off or require the password like you see in watchos 7 when wrist detection is off. i believe right now only the apple watch series 1 and 2 are limited to watchos 6 so any bug correction would only be applicable to them, for apple watchos 7 is the "bug correction" and is free and available now for series 3 and newer.