Thats fair I dont know why its happening something to do with my Photoshop, Ive have this issue before and unsure why its doin it.
Your image still has some artifacts on the transparent layer, and one accidental pixel of a colour out of the palette. Please fix it, otherwise we will have to remove the piece from the poll. This won't be pleasure to us, since your work is amazing, but leaving it might seem unfair to other participants, especially if your artwork reaches the podium.
No worries! I work with Aseprite so it's apparently not a program issue for the most part, must be a weird layer issue? If you use layers, at least. I like to upload my piece to the image checking tool before I upload here just in case and so I can grab the color amount.
Thanks for your support. I use Photoshop so sometimes the colors get mixed a bit when I work. Will work to better with this.
Wow, this one is epic! I'm amazed how much you were able to pull off in just one week. 
I LOVE this, they look amazing!! Great work!
This is extreamly well done, a lot of amazing horses this challenge