Earlier quoted context omitted.
It's very simple: 1) software renders not Unicode characters but font glyphs 2) which font glyphs are chosen depends on many factors like installed fonts, OS, language/region settings, and so on 3) people author (and read) characters by how they look on their systems, what codepoints are used is not on anyone's mind A differently configured system can uncover incorrect codepoint choices or rendering differences acros…
That happens if you have no language hints, or the wrong one, e.g. posting in Simplified Chinese on a Taiwanese website. If this was written in something like MSWord by CCP officials, it should have the proper language hint, so render properly on any OS newer than XP.
Setting aside all other assumptions you make about the soundness of their setup overall, consistency of their input methods, newness of their inventory, etc., do you actually believe they would have the fonts with traditional glyphs in them installed and used at all? What for? Remember, this applies to the system as a whole. A character would be shown as simplified by the system even during input.
Again, I tried it and I got different results in different software (even on a Mac), with Pages in particular showing only simplified characters and straight layout (in contrast to Quick Look, which is what the tweeter must have used). Do you seriously think CCP officials have a fleet of Macs to check document appearance in case they are leaked and/or scan documents for "enemy" Unicode points? If not, how they would even know what code points are there, if all they ever see is simplified?
One needs to look at vocabulary, word choices and such. That is something that could actually point to fakery. Nothing like that was claimed yet, of course.