This is correct behavior. There must be a name for this effect of having some more or less shallow understanding and feeling like an actual expert with decades of experience from various sides of the topic.

SWEs I think are more susceptible to this since as you say we often dip in many areas and industries. No, we are not actual SMEs and proper experts (barring exceptions of course, but in any case we usually have a specific view on domain, while proper experts understand many/all views).