This is not a bug. Each column of pixels in the color picker corresponds to an integer Hue value between 0 and 359. The far right column is hue = 0. The far left is hue = 359. Though they’re very close, they aren’t the same angle on the color wheel, so they produce different colors.
The way to “solve” this would be to add another column of pixels corresponding to hue = 360, which produces the same color as does hue = 0. However, this is ugly because now there are multiple HSL configurations that determine the same 255,0,0 RGB color.
Yeah, I saw this issue a while back and I’m not sure if they’re going to fix it anytime soon. It’s not really the most concerning to me but I just thought it was a little odd.