Short story:
Compare the question revision against the answer revision. Answer revisions have no syntax highlighting.
Long story:
Have a Q&A with some code, for instance this favorite one
Now go to revisions of the question and then to the formatted revision (as in picture below)
Check the code syntax highlighting - it should be ok
Now go to revisions of the answer and then to the formatted revision (as in picture above)
Check the code syntax highlighting - it's not ok, there's no coloring of the code
I know this problem is here for a long time, at least since when I signed up. The syntax highlighting works only for question revisions, not for answers. Could you check and fix this, if it's not intentional ?