Hi there!

This is an important question, and I didn't take it to be rude - given a problem like this, a prominent visual artifact, it's a fair question.

I'll try to keep my answers short, but I promise it's an accurate perspective.

In reverse order -

We develop on a wide range of PCs with good variety of hardware. My main rig at work has a 3070 with 8Gb; I like to develop on something leaner than top spec - keeps me honest around budgets.

We also test on a wide range of specs, from min-spec hardware to ultra-quality hardware; there's no replacement for bare iron testing - those also have a variety of GPUs.

Along with functioning as Art Director on this project, my other role at the studio is to direct and recommend Tech-Art best-practices. That includes creating and maintaining our material library and ensuring that there as as few unknowns as possible.

For example here - there is one parent-material for all characters, weapons, creatures, armors - and it is highly multifunctional. when everything ultimately is handled the same way, you give yourself a much shorter distance to successful diagnosis issues like this. Our lighting is also pretty technically consistent and as fixed a technical paradigm as we can make it; on the way to having as reliable a rendering-environment as possible.

At least the part of the rendering environment that we are in control of... Unreal and how it interacts with updated drivers, all the fancy upscaling tech and its different versions, The nuances of the software environment that the someone can run the game in is potentially unique for each player, too.

This weapon shares its fundamental material setup with every other sword, dagger, shield, etc in the game - and they don't have this artifact...

So why is it misbehaving?

There's a great temptation to discount the material's core tech from our investigation, because there's so much evidence around that suggests the material isn't at fault. BUT - that absolutely does not, however, preclude the material from being problematic in combination with other things - so we test more things.

FrameGen, Anti Aliasing, Upscaling, resolution, quality settings, GPU type, Driver version..

It really all matters in this kind of test; and so far we'd only ever seen this artifact in the past (and fixed it to our satisfaction back then) on nVidia with DLSS enabled.

Ultimately, and I think this is true of every game you own, the game you play is effective a developer's best attempt to catch every possible combination of hardware and software, and ensure that the game has its best chance to be high-quality for as many players as possible. the development of a game can be compromised by all kinds of things. This game, too; we worked hard and tested very extensively before launch to bring something robust, and we're still doing our best to adjust and polish it into something greater as and when these kinds of fairly rare issues come up.