The text although display in the right order, cannot be selected in the correct order. 

In the following pdf: 

www.cs.st-andrews.ac.uk/~mirco/papers/simplex10.pdf

On the second page, the selection (under Evince) goes in the following order: 

upper left -> upper right -> lower left -> lover right

Now, this might not seem a serious problem, but it hinders the use of Orca with Evince to read pdfs, since the text is read in the wrong order. 

There is also another example here: (not quite the same)

www.cs.st-andrews.ac.uk/~mirco/papers/wosn10.pdf  

On the first page, the names of the authors are read and can be selected as if they would be in columns, but the text is put on the buffer in lines. 

I could provide further info if necessary.
Cheers
M