[NoMoreNicksLeft]

>Opening them in anything else, like Chrome, showed a different single page that said to open it in Adobe Reader.

So they intentionally broke the documents for anything not Reader?

[exmadscientist]

There are multiple PDF standards. It is possible to rig up documents that display differently depending on which standards are supported. Acrobat is (or at least used to be) the only thing which truly supports them all.