Rewatching Columbina and notice how the pigeon in front of her glitching.

I personally think the glitching dove is Columbina's past self. First of all, we know that the trailer is showing Columbina's journey. We also know she calls her past self a lost dove in the latest AQ. And finally, >! we know that Columbina hid her divinity upon the frost moon while she was trapped in the moons reflection. Here we see the dove looking at her winged, goddess form trapped by strings. Just like how the past Columbina used to look longingly up towards her moon, the place where Columbina, trapped in the moon's reflection sealed her divinity on the moon. !< So the glitching dove which we see throughout the trailer represents the innocent past columbina representing the >!time shenanigans in the AQ which would also have resulted in another Columbina in the past.!< The glitching could be representing to how she was being rejected by the world and was fading out of existance.

Highly likely its a representation of the moon because the entire trailer she chases after its feather and when she finally reaches it, it turns out to be fake and she gets captured, just like the events in the AQ.

One day, after dinner, while my younger sister and I were lounging about in Mr. Gopher Wood's yard, we spotted a fledgling Charmony Dove all on its own. That baby bird was tiny, it didn't even have all of its feathers, and it couldn't sing. When we found it, it was already on its last breath, having fallen into a shrub — probably abandoned by its parents. We decided to build a nest for it right there and then. However, thinking back, that winter was unusually cold, with fierce winds at night in the yard, not to mention the many poisonous bugs and wild beasts in the vicinity... It was clear that if we left the fledgling in the yard, it stood no chance of surviving until spring. So, I suggested we take it inside, place it on the shelf by the window, and asked the adults to fashion a cage for it. We decided that when it regained its strength enough to spread its wings, we would release it back into the wild. The tragic part — something that we'd never considered — was that this bird's fate had already been determined long before this moment... Its destiny was determined by our momentary whim. Now, I pass the power of choice to you all. Faced with this situation, what choice would you make? Stick to the original plan, and build a nest with soft net where the Charmony Dove fell? Or build a cage for it, and feed it, giving it the utmost care from within the warmth of a home? I eagerly await your answer.

"Vagrancy" is the living of the land beneath the moon.
That's part of the description of all the Vagrancy talent books from the Lightless Capital domain. Their symbol is a pidgeon/dove.

All the talent books from that domain are really interesting and their respective drawings are all tied to Columbina: a dove, moonlight and elysium (that last on also has a giant bird).

That pose is also the origin of the Frostmoon Scion's greeting.