This is a screenshot of what we saw.
https://puu.sh/qVj1N/f13709a273.png
The nasty page only happened once, but we have had this happen other times where the page didn't display correctly:
https://puu.sh/qVjM5/42e934c83c.png
https://puu.sh/qVHxW/82585550ae.png
https://puu.sh/qVHpP/15433d774f.png
The computer has been scanned for viruses and malware and came back clean.
Thank!
This is an issue with Tumblr, not Minecraft.