As soon as you work as artist in the creative industry you need to be aware that if you sell your style and it will become an IP, it definitely will be copied.
All sufficiently big IPs have style guidelines. So multiple artists can create something in the look&feel of that IP.

-artist B who gets hired then randomly copy artist A's other work is a bad move from artist B.
-The company directly instructing artist B to plagiarize artist A's other work is scummy.
-The company just trying to finish their project in artists A's style is to be expected and normal in the industry

Usually a company hires someone to create a style. This person could be an artist. If that artist leaves halfway through, the project won't change the visual identity anymore and the company usually has to keep the style.
It's for sure a morally difficult to answer, but artist A sold their style.

I don't fully understand the situation. Is it like this?
There is artist A
Artist A works on GameX and also creates private art.
Artist A quits on GameX
Company hires artist B to continue artist A's job
Artist B copies artist A's personal work to put it in gameX?

For example the Lion's King game on the SNES. Disney even delivered pencil roughs for the animation, some they took directly from the movie. Sprite artists went in and "had" to trace over those roughs. It was a creative requirement. The original animators had provided their work to the IP & Disney.

That's the way how creative projects are made. For people who buy a creative product, they don't care about the artists. They usually care about the direction.
If you're an artist in any creative industry, you need to be aware that all the art you contribute to projects is not fully yours anymore.

If the commercial project is a sequel, you'll be sometimes even asked to trace/remake existing work (closely), to keep the IPs direction.

If the commercial project is new and should stand on its own feet and stand out, a general style has to be developed, tracing becomes then a creative issue.

"The Void"

A few things I used are already on my Ko-Fi.
For everything deeper I offer my services as graphics consultant.

Amongs tmany other things I made a collection with examples of cheaper assets which look really good and on the other hand quite expensive assets which look bad in comparison and went into the why.
Also I talked about non obvious art timesinks which come as a surprise to many technical people.

We create pixel art for games. Its named for beginners because thats hkw we started 3 years ago. We made a lot of art for our game Occult Office in the stream for the last 9 months store.steampowered.com/app/3897770/...

Can it be, that a lot of images got deleted or is this just a temporary problem? Got a few E-mails.