Skorpion taillights are a problem, both of them.
After a few not very episodes with various diode taillights that also could not take the vibes, I bought a Hella taillight made for trailers and traktors. Outside of the EU, it is probably not an option but such round or oval "heavy-duty" stuff is made for the same purposes in the States.
The Hella is all-metal with threaded screws and two separate bulbs.
It has caused no trouble at all, not even a replacement bulb.