What sort of bulb are you using? If the bulb is a flourescent bulb, there will invariably be a delay before they come on, as the bulb begins to age.
"10 year" bulbs don't mean that they'll provide good light for that entire period of time, sadly, and they will begin to slow down on lighting as time goes on, some worse than others. Try switching the bulb for a standard incandescent bulb, and see if the error continues.
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What sort of bulb are you using? If the bulb is a flourescent bulb, there will invariably be a delay before they come on, as the bulb begins to age.
"10 year" bulbs don't mean that they'll provide good light for that entire period of time, sadly, and they will begin to slow down on lighting as time goes on, some worse than others. Try switching the bulb for a standard incandescent bulb, and see if the error continues.