Rockets in-flight should remain in flight if shooter dies

I'm at a loss that I found something to agree with you about! 

In all seriousness... I have been told it was due to an old upgrade.  And it ticks me off too... several times it could have made the difference in a game.  Especially 1 v 1 duels over a beacon.

Apparently, having them remain kept on causing unfixable bugs.

Yes, realistically once you've fired one then a projectile should exist on it's own merit regardless of what happens to it's origin. That's not the only bit of reality that's been short-cut on behalf of the rule-of-cool (and playability) in this game. For example although we have clips on most weapons, the ammunition is infinite. A 4xPinata Patton should have a few building-sized trucks following it around with all the spare missiles, yanno?

That said, it's not just the missiles. From my observations, all projectiles fired from a bot immediately vanish once the bot dies. From a hobbyist programming perspective, it actually does make some sense. By slaving all the projectiles fired by a bot to that bot, it makes for a very easy 'clean up' of child-objects when the bot is destroyed. Bugs from 'orphaned' projectiles? I totally believe it, and have seen it in other 3/FPS games before. Now, I wasn't there to see any of it in this game, but I could easily imagine the havoc created if say a missile got 'orphaned' at the exact moment of impact creating a persistent and continuous explosion at that spot that lasted for the remainder of the round. And that's just one example. Bugs are harbingers of Chaos.

I've been saved once or twice, or maybe a few dozen times, from getting slammed in the face with something because I was a quarter second quicker to reload or fire.
I've always seen both players die more than I believe both ran out of HP at exactly the same moment. I've never paid attention to ranges that closely when it occurs but I'd be interested to guesstimate it now and see if it happens more often from closer than further. Like the server doesn't receive the destroyed information before the orphaned weapons hit.

Must not be fire and forget - lol

Could they not just create a rule that despawns them after a set amount of time existing? Or a rule that only allows one impact from the shell and despawn it if it attempts to make another?

As a non-programmer I have no idea how feasible what I said is. If I'm being a moron then just ignore me 

This always puzzled me too, how hard could it be? But it's a relatively minor thing which must be harder than it looks to fix, because clearly Pix has deemed it not worth their time.

they haven't deemed it worth their time to fix Zeus either. It's been months.

It depends a bit on how they set up the code.  If there's a very strict parent/child or slaving hierarchy, then having to re-child/slave the item and conveying that across server/clients can be a pain in the butt.  That said, it's not exactly hard.  Just annoying, with potential for other glitches and a whole lot of additional conditional logic where before there was none.  If they've looked at it before and decided it wasn't worth their time, then they probably coded themselves into a bit of a hole and just aren't touching it until some more major overhaul.  Think rewriting it, rather than patching it.

Edit: I knew I had a screenshot somewhere.  This isn't a weapon per se, although I think it's one of them cartridges that get expelled?  I don't think it's a piece of bot as there's no corpse anywhere around.  Regardless, this object was probably a child of another object that went poof, so it got orphaned and then the code just doesn't know what to do with it as, for all intents and purposes other than rendering client-side, it doesn't exist.  So it just stays there in limbo, floating around in mid-air;