I don't think you're seeing what you think you are seeing (or I'm missing something).
Lua Code:
local f = CreateFrame('Statusbar', nil, UIParent)
f:SetSize(100, 20)
f:SetPoint('CENTER')
f:SetMinMaxValues(0, 100)
f:SetStatusBarTexture("Interface/BUTTONS/WHITE8X8")
f:SetStatusBarColor(1, 0, 0)
f:SetValue(50)
local g = CreateFrame('StatusBar', nil, UIParent)
g:SetSize(100, 20)
g:SetPoint('CENTER', 0, - 30)
g:SetMinMaxValues(0, 100)
g:SetValue(60)
g:SetStatusBarTexture("Interface/BUTTONS/WHITE8X8")
g:SetStatusBarColor(0.5, 0.5, 0)
--
g.texture = g:CreateTexture(nil, 'BORDER')
g.texture:SetSize(20, 20)
g.texture:SetPoint("LEFT", g, "RIGHT", 10, 0)
g.texture:SetTexture("Interface/BUTTONS/WHITE8X8")
g.texture:SetColorTexture(0, 0, 1)
g:SetStatusBarColor(g.texture)
local h = CreateFrame('Frame', nil, UIParent)
h:SetSize(100, 20)
h:SetPoint('CENTER', 0, -60)
h.texture = h:CreateTexture(nil, 'BORDER')
h.texture:SetAllPoints()
h.texture:SetColorTexture(0, 1, 0)
I don't know oUF but if it lets you set a status bar colour using a texture widget maybe it is using a custom startusbar creation and not the default StatusBar widget.