In T96154#1316921, @Richard Antalik (ISS) wrote:

After checking code I don't see such feature implemented.

So if it is not feature, it is a bug.
Why did you closed report?

What I said in other words is, that as far as I can see, this feature was never meant to do, what you want from it.

I think the problem here is with the Blender Docs. The docs need to mention that the selected UV map will be used to bake data onto the target texture, and a UV map is not required for baking to vertex colors. The vector input of the target image texture node does not effect the bake.

In T96154#1316946, @Ethan Hall (Ethan1080) wrote:

I think the problem here is with the Blender Docs. The docs need to mention that the UV map marked as Active Render

But it use selected, not active for render (camera icon)!
Also it should bake what user see with current the shader. Not something, that connected by obscure rule!

So please reopen! As papercut, bug, todo, no matter. This is huge issue with baking now!

In T96154#1317140, @Vyacheslav (hitrpr) wrote:

But it use selected, not active for render (camera icon)!

Oops, you are right about that.

Also it should bake what user see with current the shader. Not something, that connected by obscure rule!

There is a good reason why baking doesn't evaluate the input of the target Image Texture Node. The input on the Image Texture Node can be anything, not just UV maps. However, baking to a texture only makes sense with UV maps. Using the UV map marked as Active Render would make more sense to me though. The documentation definitely needs to be more clear in any case.

In T96154#1317254, @Ethan Hall (Ethan1080) wrote:

In T96154#1317140, @Vyacheslav (hitrpr) wrote:

Using the UV map marked as Active Render would make more sense to me though.

The issue, that render icon is «UV that rendered», donor, source, not recipient!
Also few UVs can be recipients.
I supose that is why developers made selected UV as target.
IDK where UV with render icon actually used and why icon can be inly switched.

Yes, it is usual case is baking from few UV`s and textures to one texture and UV.
But what if I need to bake few materials, from few UV`s to 2 different UV`s? One target UV for albedo (more detailed)
and one for normals (more optimized, mirrored).
Is it even possible with current system «only one target»?

Now all looks like abandoned part, and it needs good system design.
It is not about bug, right. But still about design, UI, UX