P: PDF import show edge artifacts on tiled PDF images (bug in PDF creation)

No, CS5 just shows the artifacts at different resolutions and different strengths because of the sloppy way that CS5 was handling antialiasing when rasterizing PDF.
Please read the previous comments - I've already been over this a few dozen times.

You aren't reading my responses, I've already answered that a dozen times.
YES, the defects exist in the PDF file. Photoshop did not create those files, we cannot fix the code that created those files - we have to wait for other teams to understand and fix their bugs.

Chris,
I repeat!
"Still you haven't answered the most important question regarding PDF files with flatten transparency: DO THE THIN LINES IN THE PDF FILES REALLY EXIST? NOW we take the responsibility for what you have created and you can't or you don't want to repair."

Read the other questions above and answer me, please.

And I open the file in original 300dpi and I have lines, so...?????

Just tried again.
Placing a PDF file in Photoshop CS5 as smart object shows no artefacts/lines.
Opening this data in CS6 shows no artefacts/lines.
But placing the same PDF file in CS6 shows artefacts/lines.
So, CS5 is doing something better than CS6.

Again, I have researched this, and I can find the artifacts in CS5 (and the customer complaints) and earlier versions. The defects in the files can show up in any version of Photoshop, and in other applications.

The CS6 rasterization improvements just happen to make these artifacts show up more often, along with improving the quality of the rasterization.

No. In CS5 it works fine here.
CS6 is not usable because of that. So the "improvements" are not really that good...

The files you have are not likely to render without artifacts except at high resolution. The image slicing that was applied to them just does not allow for correct rasterization except at the original resolution or higher resolution.

Dear Chris!
Finally you have given some facts but maybe you should invite the bosses of other teams to our discussion. If they see our conversation, they will decide to react and you won't have to make any excuses for the other teams.

Can you tell me how much time will the other teams need (approximately) in order to react for that BUG? Will it take another year?

Still you haven't answered the most important question regarding PDF files with flatten transparency: DO THE THIN LINES IN THE PDF FILES REALLY EXIST? It would be good if you took the responsibility for the software you create. NOW we take the responsibility for what you have created and you can't or you don't want to repair. I would like to remind you that we have paid for the software a lot of money. Since we have paid for it quite a lot of money it would be nice if it worked properly without any obstacles.

To finish with, one more question. Is there chance to render PDF files properly without loss of the quality (it concerns the problem of the unchecking "smooth" in PDF import dialogue box which worsens the render quality)?

I've said repeatedly that we're working on it. But I can't guarantee a fix because I have to depend on other teams to fix their code.

No, you can see artifacts in CS5 and older versions of Photoshop as well for these documents. The artifacts just aren't as obvious, and happen at different resolutions due to the improvements made to rasterization in CS6.