Illlustrator CC can't save back to Illustrator 3...

Question

I have a file that was created sometime ago (Illustrator CS5-ish). I am able to open the file in CC just fine. I open the file and then:
convert all of the type to outlines
delete a background box that contains a gradient (no other gradients exist)
flatten the file so it only contains one layer
delete unused panel items
make sure all strokes are converted to outlines
Double-checking the file I make sure there are no stray text paths.
When I save back to Illustrator 3, I get the usual warning about saving to a legacy version. To test the file I try to reopen the file with CC at which point I receive the error:
Offending operator: {ps_metadata_stream}
Context: Ǫè
When I go back through the entire process and try to save the file to Illustrator 8, upon opening the file I receive the error:
Offending operator: {ps_metadata_stream}
Context: ı©7
It wasn't until I ungrouped everything (5 nested groups) and then tried to save the file to versions 3 and 8 that it actually allowed me to open the files again. The only reason I thought to try and remove the groups was because I was trying to remember what current features were actually supported in version 3 (not a lot of them); that's been a really long time ago.
Apparently Illustrator CC doesn't dilligently reduce files for compatibility. I had to save to this older version for sending to one of my clients who uses a cad software (SolidWorks) for importing the graphics into models.
Hope this helps someone.

Answer 1

Thanks Raghuveer,
I received your e-mail and am uploading the files presently.
When trying to replicate my results, (thought I had documented everything), I didn't get them at first when trying to save the files out for you. Then I noticed what was happening....
When I use "Save As Copy" with this particular file, upon reopening the newly saved file I get no error.
When I use "Save As" and save the file in the Versions 3 or 8 format, I then get the error upon reopening.
It appears that groups have nothing to do with it.