When any addon modifies the color of the default nameplates it will cause the following error when a new nameplate is created during combat.
Code:
1x [ADDON_ACTION_BLOCKED] AddOn '!Colorz' tried to call the protected function 'SetTargetClampingInsets()'.
!BugGrabber\BugGrabber.lua:573: in function <!BugGrabber\BugGrabber.lua:573>
[C]: in function `SetTargetClampingInsets'
...eBlizzard_NamePlates\Blizzard_NamePlates.lua:221: in function `SetupClassNameplateBars'
...eBlizzard_NamePlates\Blizzard_NamePlates.lua:74: in function `OnNamePlateAdded'
...eBlizzard_NamePlates\Blizzard_NamePlates.lua:38: in function <...eBlizzard_NamePlates\Blizzard_NamePlates.lua:32>
This seems be true no matter how the code works. Directly setting the status bar color, setting DefaultCompactNamePlate(Friendly/Enemy)FrameOptions.useClassColors to true, or modifying UnitSelectionColor all cause the same error.