I did some testing and it appears that it is the disease section that is not pasting correctly. If you paste the Disease section all by itself it pastes but it does not keep the correct formatting (everything is bolded).
If you paste even one line from the previous (Death Burst) section then the Disease section gets that chunk taken out.
Perhaps the HTML code in that section is what is causing the problem.
Edit: I did some additional testing and it is Bolded text followed by a hyperlinked text that is the problem. I tried a number of other d20pfsrd statblocks and anytime there is a BOLD word before a Link it is not pasted correctly. Since the disease section posts entirely in bold (incorrectly) everything that is incorrectly bolded is cut off prior to the linked word.
- Gauss