The answer to 'why is my GFCI outlet flickering lights' is that a flickering or blinking GFCI outlet is often a sign of a problem with the GFCI circuit. GFCI outlets are designed to detect ground faults and trip to protect against electrical shocks, and the flickering can indicate that the GFCI is sensing a small electrical imbalance or fault.
Some common causes of a flickering GFCI outlet include a faulty GFCI, a wiring issue, or a problem with one of the devices or appliances plugged into the GFCI circuit. It's important to investigate the cause to ensure safety and prevent more serious electrical issues.