There is most definitely no problem with the surface normals - checked with the Blender + see my updated post with real life images now. :-)

Regarding image example I'll update/change those for the real thing (it'll be another simple model: just a glass and a minifig); as for the other things: as I already said: t's absolutely unimportant what glass material you use for your test as the question is elsewhere, that is if we can make somehow correction to IOR deformation afterwards, thus you really do not need to see anything as it is irrelevant...well, unless one did not understand the question. :-D Regardless what image I use it'll not change anything slightest in the question which is not made around any specific image.

I am AFOL (older LEGO enthusiast) having huge inventory of real LEGO bricks at hand, so I can recreate anything I do as CGI and compare, and the real life LEGO bricks do not distorting object behind the glass this terrible hard as on the 1st image, they do it the way you see on the 2nd image. If there would be really need for a real life LEGO bricks example I think I can make a picture, although I do not see why that should be significant regarding if I can provide it or not: you simply have to believe me that the 2nd image as for the deformation is correct one, 1st one is totally off.

Ah, so it is prolly unavoidable you say?

@3fingeredfrog 1.) have no clue what SL stands for, 2.) as you can clearly see I HAVE COPY CHECKED (!!) yet no texture (image) is exported with the .dae nor there is any reference inside the dae file for the texture (library_images tag is completely empty inside the dae file)

Sorry, but regardless of the node it still does not export textures when exporting to Collada (.dae) in Blender v3.6.4, yet dae has absolutely no problem with textures as other apps export to it with no problem incl. texture refferences for the materials.

@DavidWillo Hi, as I have the same problem with Blender v3.6.4 can you tell me in which way the link provided help you? Cos I could not take nothing from it that would help yet constantly seeing him giving that exact link for any kind of problem related to this stuff (dae not exporting images, although the texture option COPY is checked). I am really trying here to understand how, in what way or form the info there helped you so that I can use it for my problem of the same kind now in year 2023.

@DuarteFarrajotaRamos that link has nothing to do with Blender being unable exporting textures with dae or obj - the texture option COPY is checked yet it does not help with Blender v3.6.4. It looks more like another Blender export bug.