This is a tricky problem, but the consistent "fix" of disconnecting and reconnecting the ballast points us strongly in that direction. Here's a breakdown of possible causes and troubleshooting steps, focusing on the fact that a power cycle "fixes" it temporarily

Possible Causes:

1. Failing Ballast (Most Likely)

LED ballasts, like traditional ones, can fail intermittently. The fact that a disconnect/reconnect temporarily resolves the issue strongly suggests the ballast has an internal fault or component weakening. It's not unusual for they to have issues due to heat or the power load. This is the most likely explanation, even though it seems odd that it's only 5 specific fixtures and not all of them.2.

Marginal Voltage

Even though you said everything's on the same switch leg, there could be a slight voltage drop at the end of the run, specifically affecting the ballasts controlling those 5 center lights. LED ballasts are generally more sensitive to voltage fluctuations than older fluorescent ballasts.3.

Loose Wiring (Less Likely, but important to check)

A loose connection somewhere in the wiring before these fixtures could be contributing. Vibration, temperature changes, or corrosion might cause intermittent contact. Disconnecting and reconnecting the ballast might temporarily improve the connection. Specifically, check the neutral wire for the circuit.4.

Heat Buildup

If the fixtures are in a location with poor ventilation, the ballasts for the center lamps might be overheating. This could cause them to shut down temporarily. The cooling-down period after disconnecting/reconnecting allows them to function again until they overheat.5.

Compatible lamps/ballasts: Ensure your LED lamps and ballasts are compatible. Check the manufacturer's specifications.

Troubleshooting Steps


Voltage Measurement



Measure the voltage at the ballasts of a "good" fixture (center lamp always works) and one of the "bad" fixtures (center lamp fails). Do this while the lamps are supposed to be on. A significant difference in voltage (even a few volts) could point to a wiring issue or voltage drop. Measure voltage line to neutral and line to ground. Measure the voltage at the first fixture on the circuit and the last fixture on the circuit. This will give you an overall sense of voltage drop across the circuit. Record your readings.2. Inspect Wiring Closely



Turn OFF the breaker before doing any wiring work! Check all wiring connections to the ballasts for the failing center lights. Look for loose wires, corroded terminals, or signs of overheating (discoloration, burnt insulation). Pay special attention to push-in connectors (wire nuts are better) as they can loosen over time. Check the switch itself. The switch could be faulty. Check the wiring to the switch and the breaker panel. Look for any loose or corroded connections. Pay special attention to the neutral wire (white) and ground wire (green). A loose neutral is a common culprit in these types of intermittent problems.3. Ballast Swapping (Diagnostic)



Important

Ensure the ballasts you're swapping are identical models.

Swap a ballast from a "good" fixture (center lamp always works) with a ballast from a "bad" fixture (center lamp fails). Make careful notes of which ballast came from where. Monitor the fixtures. If the problem follows the ballast, you've confirmed the ballast is faulty. If the problem stays with the fixture, the wiring or voltage is the issue.4. Heat Check



Monitor the temperature of the ballasts in the "bad" fixtures. Use a non-contact infrared thermometer (temperature gun) to compare the temperature of the ballasts in a working fixture vs. a failing fixture after they've been on for a while.5. Test Lamps

It is unlikely to be the lamps but, swap the lamps from a "good" fixture with lamps from a "bad" fixture to rule out a lamp issue.

Important Safety Notes



Always turn OFF the power at the breaker before working on any electrical wiring. If you are not comfortable working with electricity, hire a qualified electrician.

Conclusion:

Based on the information you've provided, a failing ballast is the most likely* cause. Follow the troubleshooting steps above, starting with voltage measurements and then moving to ballast swapping. Be methodical and document your findings. Good luck! Flag for review