The problem with the ones I've been using is that they're fully exposed. These Diode Dynamics ones are slightly more enclosed, but still open. Just enough moisture or water or something must be getting into the housing to corrode the circuitry. I find rust on the weld points on the LEDs I use once they are starting to flicker.I bought some in October or November. Both are already no good.
I just bought these and they arrived today: https://www.amazon.ca/gp/product/B017VORB7M
They're very bright. They have small holes on either side and the cap on the top isn't sealed to the base. I'm sure those holes are there to allow heat to dissipate, but in my case I don't have an option. I'm going to use a glue gun and plug up the holes and seal up the entire thing basically and see what happens. I'm also putting dielectric grease in the bulb socket to assist in corrosion prevention as even the copper contacts in the socket have corrosion on them after a while. I really don't know for sure where the moisture/water is coming in from. Maybe travelling down the wire and into the housing? I put silicone on the wires a while back to block any holes where water may be coming in to we'll see if that solves the problem.
Oh well. What's done is done. I'm sure once I seal these Phillips LEDs up they'll work fine. I've always had positive experiences with any of Phillips' products.