Okay so, this is the first time I've ever reported something like this on the Phabricator so, please forgive me if I did anything wrong.
But anyways...

This bug (at least, I think it's a bug...) has been happening ever since I got the most recent update, and I've decided to demonstrate the issue right here:

Fig. 1
http://i.imgur.com/MIygbuU.png
The first of 3 identical testbeds I'll be using to reproduce this bug.
Note that this one has a forwards facing damage beam computer slaved to a downwards facing missile computer.

Fig. 2
http://i.imgur.com/7BmMYTk.png
The second of 3 identical testbeds, this time having both forwards facing damage beam and missile computers.

Fig. 3
http://i.imgur.com/7STpwGc.png
The third and final testbed (on the horizon). Simply put, this one will act as our target.

Test 1
http://i.imgur.com/qrarfOP.png

Attempting to shoot the target using the first testbed
(forward facing Beam Computer, downwards facing Missile Computer)

While I (unfortunately) wasn't able to get a proper screenshot of this test, the missile was able to be fired successfully at first, only for it to suddenly disappear into thin air (or lack thereof? I dunno) after arching for a bit, not even managing to hit its target.

Take note that I was able to replicate this at greater and lesser distances, including firing it on point blank range at the target at one point.

Test 2
http://i.imgur.com/o1QuAgn.png
Shooting the target with the second testbed.
(forward facing beam and missile computers)

Was able to get a... somewhat proper screenshot this time around but, as you can see, everything worked here as it should, and I was able to hit the target (multiple times, in fact), as seen here:
http://i.imgur.com/5RCF9iG.png

Long story short, while normal forward-facing smart/lock-on missiles still worked, non-forward facing arcing missiles have been broken as all hell since the update.