I thought you'd quit?
https://forums.frontier.co.uk/showthread.php/314205-Good-Riddence
If it was "Cmdr Brett Reynolds" then yes there may be a bug or hack or a very skilled pilot. But naming and shaming means this post isn't allowed by forum rules so you'd have to remove the name. Engineered torpedoes can instantly drop shields and some engineered weapons will just shred you if you arn't expecting it. I doubt it was a player but just to say this is quite a possible scenario for PvP combat. Nuf said there.
If it was just "Brett Reynolds" (which is what I expect) then its either his weapons or your ship build. One or the other caused this, probably a combination of both.
I'd bet most of my ill gotten gains that the FDS was using missiles or torpedoes in at least 2 slots with plasma accelerators or railguns in the others or some high insta damage weapons, maybe frag cannons. Bearing in mind a class 4 plasma kills an eagle in 1 shot if he used a C3 plasma and 2x class 2 railguns to wipe your shields instantly, then a missile barrage it's conceivable that you got slapped down really hard by just a high alpha damage loadout.
Something important here:
hull health does not equal module health. You can be at 100% hull and have modules failing everywhere or conversely be at 1% hull with your modules pristine. Explosives damage all the modules on the outside of your ship, all weapons and all utilities as well as thrusters. Yes you hit him with missiles but NPC's have a habit of ignoring certain things and pressing on where a human would be panicking (advantages of being a robot). Instead of being scared when everything malfunctions and overheats at 500% they simply align their weapons and carry on doing damage instantly disabling/enabling the right things to keep fighting as they are machines. Also with the new update there's a module reinforcement package that you can use, a few of these will make all the difference to keep a ship flying that would otherwise be crippled, could be another factor. Not sure if NPCs use these as they only got added in 2.2.03 but tbh I imagine they do use it especially on ships with strong hull in the first place like the Fed ships...
As above the Dropship has 4 medium mounts, even if only 2 of these were missiles landing a few good hits with dumbfires will cripple any ship that doesn't have point defence or shields. I'd again place bad money on your build being a heavy shield tank build with no hull/module reinforcement packages. Once your shields were down you were a sitting duck as reinforced armour is not match against weapons designed to take out armour.
You say your shields went down quick and so did your hull, that to me fires off a bunch of questions as Python is a good medium ship that can have incredible hull and shields if outfitted and flown right:
What was your pip layout?
Did you have hull packages?
What was the enemy rank?
Did you see his weapons/loadout?
Overall I can only agree with StiTch above, without a video or even a ship-build all we can do is make educated guesses. Even looking at what I wrote above there's about 30 things we don't know that could be the key point. I don't think my guesses are far off the mark but for all I know you could have hit the glitch in the matrix.
My final point here: If there truly were invincible NPC's then you'd have thought the whole forum and reddit would be blowing up about it.... Well do a google... There isn't anyone else having this issue from what we can see? Why isn't everywhere full of: 2.2.03 broke the game...