Alexander of Macedon said:
It's an uncommon visual bug with PPCs fired in this general situation (from behind the player's perspective at a point forward of them).
Since I never bothered looking at PPC flashes from a side angle I also cannot comment on how common or uncommon that particular rendering bug is overall. And it's still irritating even when suspecting or actually knowing about the existance of such a bug simply because it defies expectations our human brains apply to these visuals.
Alexander of Macedon said:
All that aside, however, there are incidental things that indicate exactly what's happening: there's an assault parked somewhere upslope of the streamer, PPC sounds are triggering behind him every time those shots appear, and the effects of the PPC trail become noticeably thinner as it moves from where it "appears" to the target.
Which is all fine and ties in with pretty much everyone's explaination in case where it actually was attempted to give one. The main problem with most of the explainations however was that everyone was eager to share the info where the ppc firing mech most likely was positioned based on map knowledge and audio cues but noone cared to spell out the elephant in the room: Why a mech firing from that position would actually create those "abnormal" visuals.
To make things worse ...
Alexander of Macedon said:
If it was really what OP seems to be implying, a cheat that allows someone to fire PPCs from the skybox down at targets, the PPC trail would stay the same width and there wouldn't be any audio cue for someone as far away as the streamer.
... you even outright assumed that the OP was implying foul play and - despite having acknowledged by now via a secondary post that this wasn't actually the case - haven't bothered with (publically) appologizing for that unwarranted negative assumption.
For me this is one of the cases where someone indeed made an
*** out of
u and
me where
u is literally
you and
me is the OP. It's also a good reminder that sometimes it would be better for this forum (or any other forum for that matter) if people took a step back before making such assumption and / or brushing off questions just because they individually are reasonably certain about knowing the "correct" answer but then out-right fail at actually providing the real explaination to the question at hand.
The answer to the question was actually not "
there's a mech on higher ground to right and slightly behind the spectated mech" but "
there's a (decently well known) render problem with the ppc shots fired by that mech on higher ground to the right and slightly behind the spectated mech" and not everyone can and will by default be able to make the connection that you (and others) do seem to consider to be trivial.
Alexander of Macedon said:
The visual bug/desync causes a very minor trick of perspective that five seconds of thinking can resolve, essentially.
I'll just leave it at this: Coming to the conclusion that there must be a render bug involved is not as trivial as you make this out to be and five seconds for doing so is certainly not the average time it'll take the majority of people who are confronted with this phenomenon for the very first time simply because watching the relevant sections of video already takes longer than that.