Html – Why the images and animation disappear if I add a class to the last column

I am trying to animate in an infinite loop 6 images.

When I add the 6th image and if I add the "poster" class, none of the images are displayed, but if I omit adding the "poster" class to the 6th column (or image), the first 5 images display and animate correctly.

I don’t understand why this happens.

CSS

@keyframes moves {
  to {
    background-position: -100vw 80%;
  }
}

.galería {
  position: relative;
  overflow: hidden;
}

.poster {
  position: absolute;
  animation: moveAcross 6s linear infinite;
}
.poster-1 {
  animation-delay: -0s;
  animation-duration: 6s;
}
.poster-2 {
  animation-delay: -1s;
  animation-duration: 6s;
}
.poster-3 {
  animation-delay: -2s;
  animation-duration: 6s;
}
.poster-4 {
  animation-delay: -3s;
  animation-duration: 6s;
}
.poster-5 {
  animation-delay: -4s;
  animation-duration: 6s;
}
.poster-6 {
  animation-delay: -5s;
  animation-duration: 6s;
}

@keyframes moveAcross {
  0% {
    left: -300px;
  }
  100% {
    left: 110%;
  }
}

HTML

<div class="row justify-content-center">
    <div class="galeria">
        <div class="col poster poster-1">
            <img src="images/posters/poster1.jpg" class="img-fluid" />
        </div>
        <div class="col poster poster-2 ">
            <img src="images/posters/poster2.jpg" class="img-fluid" />
        </div>
        <div class="col poster poster-3">
            <img src="images/posters/poster3.jpg" class="img-fluid" />
        </div>
        <div class="col poster poster-4 ">
            <img src="images/posters/poster4.jpg" class="img-fluid" />
        </div>
        <div class="col poster poster-5">
            <img src="images/posters/poster5.jpg" class="img-fluid" />
        </div>
        <div class="col poster-6">
            <img src="images/posters/poster6.jpg" class="img-fluid" />
        </div>
    </div>
</div>

As you can see, the "poster" class is not in the sixth column, so my code works, but as soon as I add that class, it stops working.

(I’m working with bootstrap 5 but I’m sure it has nothing to do with this problemo, since the code, as I present it, replicates the problem perfectly)