Not a bipolar trait.
Something like grandiosity might make it easier, but it's not a trait of BP unto itself.

Consider perception and intent. Something may not be true, but not be a lie. Like...in a strong hypomania, I threw my hands to the sky and shouted, "I'm a f****** genius!!!!!!!!!" Is this a lie? No. I was just crazy full of myself. Grandiosity. (Lol, it involved a marker, aluminum foil, and glue gun --oh how it would have wowed 'em! )

Or situations of saying I'll do things. And they don't happen. Not lies. I really DO mean to do them. But I'm not having a realistic perception.

But say someone IS trying to deceive. The grandiosity and feeling of invincibility could certainly embolden them to cross the line, but it doesn't cause them to lie. Deceiving is a choice.

Lying makes me super anxious (a mix of personal code, paranoia and being terrible at it anyway). The only thing I'm good at lying about is saying things are ok when they totally aren't.