Colour pallete turning black when exporting animation into sprite sheet

Note: I am using version v1.3-rc2-x64
I made this small 16x16 animation, and decided to export this animation into a sprite sheet. After doing so, the color pallete on the left showed as 255 separate black colors. The animation i created only used 5 colors, all green, so the fact that it would expand the amount of colors so high is confusing and unnecessary.

this is very strange and almost definitely unintentional. I would also like to mention that this only happens in RGB Color mode.