Had this issue today when in suramar with my warlock:

Message: Interface\AddOns\oUF\elements\auras.lua:203: attempt to index local 'color' (a nil value)

Stack:
Interface\AddOns\oUF\elements\auras.lua:279: in function <Interface\AddOns\oUF\elements\auras.lua:273>
Interface\AddOns\oUF\elements\auras.lua:429: in function `func'
Interface\AddOns\oUF\events.lua:50: in function <Interface\AddOns\oUF\events.lua:48>
(tail call): ?

Count: 1

Locals:
element = {
0 =
PostCreateIcon = defined @interface\AddOns\oUF_Phanx\Functions.lua:458
growth-y = "UP"
createdIcons = 1
spacing-y = 12
size = 30
__owner = oUFPhanxTarget {
}
spacing-x = 6
anchoredIcons = 1
PostUpdate = defined @interface\AddOns\oUF_Phanx\Functions.lua:521
showType = true
1 = oUFPhanxTarget.DebuffsButton1 {
}
PostUpdateIcon = defined @interface\AddOns\oUF_Phanx\Functions.lua:513
visibleDebuffs = 0
ForceUpdate = defined @interface\AddOns\oUF\elements\auras.lua:471
initialAnchor = "BOTTOMLEFT"
CustomFilter = defined @interface\AddOns\oUF_Phanx\Auras.lua:833
growth-x = "RIGHT"
num = 18
}
unit = "target"
filter = "HARMFUL"
limit = 18
isDebuff = true
offset = 0
dontHide = nil
index = 1
visible = 0
hidden = 0
updateIcon = defined @interface\AddOns\oUF\elements\auras.lua:140
VISIBLE = 1
HIDDEN = 0

See #27