[semlar]

Alright, get rid of the UpdateIndicators function, leave indicatorPositions and indicatorBackdrop above the Shared function, and change the "if cfg.indicators.enable then" block to this..

if cfg.indicators.enable then
        local indicators = CreateFrame("Frame", nil ,self)
        indicators:SetAllPoints(true)
        indicators:EnableMouse(false)
        self.indicators = indicators
 
        -- Build the indicators
        for i = 1, #indicatorPositions do
                local position = indicatorPositions[i]
                local indicator = CreateFrame("Frame", nil, indicators)
                indicator:SetPoint(position)
                indicator:SetSize(5, 5)
                indicator:SetBackdrop(indicatorBackdrop)
 
                indicator.aura = cfg.indicators["aura"..i]
                indicators[position] = indicator
        end
 
        -- Register the event on the frame itself
        self:RegisterEvent("UNIT_AURA", function(self, event, unit)
            for i = 1, #indicatorPositions do
                local position = indicatorPositions[i]
                local indicator = indicators[position]
                indicator:SetShown(UnitBuff(unit, indicator.aura))
            end
        end)
end

or possibly change "local indicator = indicators[position]" to "local indicator = self.indicators[position]" in your UpdateIndicators function, try that before you replace the whole block of code.