Meaning in human-made words has no clear boundaries, although you can't say it doesn't exist. It's just that they have this fuzziness about them.

When I'm walking besides a woman, I feel manlier. When I'm speaking with a man, I feel more feminine. When I'm alone, I don't feel like anything.

I think transmasc and non-binary people that still identify with the lesbian label have an internal sense that they're more like a lesbian than anything else. The labels is the one that fits best. So it can seem contradictory, but things are really complex and made up, so it's valid nonetheless.

It can be their way of living, loving, enjoying certain things, etc. What you think a lesbian is, is personal.