I'm not sure how to approach this, so I'll just come right out with it.

There is no saying or phrase "pink elephant in the room". There is a phrase "elephant in the room", for sure. But when you add pink too it - well, that changes things. The only sayings about "pink elephants" are phrases related to people hallucinating due to drug or alcohol use. And I suspect you are not suggesting that drug or alcohol use are the issues here.

Just so you know I'm not making things up, I offer the following:

https://english.stackexchange.com/questions/104243/what-does-the-pink-elephant-in-the-room-mean

I know someone who keeps using the phrase "The pink elephant in the room". I know that phrase "The elephant in the room".
Is this the same thing? Does it mean something different?

That someone is confused.

"The elephant in the room" is a problem that everyone knows is there but no one wants to acknowledge.

A "white elephant" is a troublesome or costly possession that's hard to get rid of.

A "pink elephant" is something that people are said to see quite often when they're drunk. It's a drunken hallucination. But Urban dictionary has an entry for "The Pink Elephant in the room": it's also a hallucination.

Here's a pro tip for you. Maybe don't pound on someone for not understanding a saying and tell them to look it up until you're sure that you actually know what it means yourself.