It's a big problem especially if you haven't met the people you're working with. It's easy so think one dimensionally about a person, I catch myself doing it all the time and I can't say I'm wise enough to always stop it dead in its tracks.

I can’t say I have ever experienced this problem after conversing with someone more than a handful of times.

Sure it applies to things like random people on social media and such, but after a mutual exchange or two you should be over it.