Some led bulbs may not as reliable as others and the on board electronics possibly more prone to either total failure; or at least reduced driver output. I have an outdoor led lamp in a bulk head installation with integral PIR. The bulb failed in that housing, whilst in other non PIR areas (indoors in a garage) the dame type and wattage have lasted, are lasting, far longer. The PIR unit has frequent on/offs due to assorted critters critters triggering it (think moggies, foxes erc.). Current bulb of another brand thus far is holding up ok. Flashing led systems have different electronics and so on and are designed for that flashing operation; other bulbs not so. I’m still inclined suspect the bulb and its built in driver in this case, producing correct volts hence the problem as described. The problem with led system with non replaceable bulbs is one never knows if it’s the drivers, or the led effectively failing as any diode system can have leakage across the diode(s) or go high resistance (the latter being unlikely though). I have seen led bulbs start ti show reduced output before they actually fail (before the claimed life of sed bulb).