Terms evolve… but people also bastardize them to make a buck.
Traditionally, the concept is rooted in the idea of one soul split into two bodies, so by that definition, there’s only one. It’s right there in the name “twin”. The only time I’ve ever seen someone say they have two is that weird guy from the TFU cult who was just trying to sleep with a bunch of people.
Sometimes people just mistakenly use the term “twin flame” when they don’t really know that it is. The same way as people use “soulmate” because they heard it in a movie and it stuck as a cultural term, losing any kind of spiritual meaning.
Or if they at least have some idea, then maybe they are talking about other soul level connections, but just not an actual twin flame. These connections are meant to be catalysts for major growth, and you can definitely have more than one of those. The intensity can feel the same, so the labels get blurred by people who misunderstand what they’re feeling.
I’m all for people having different beliefs with the path, but I’m yet to see anyone with an actual, valid experience of having more than one TF.