I'm running 1.7.0_51 and have no HTML rendering issues.
Frono says he upgraded to version 60 and started seeing bad HTML rendering.
I expect that Java 8 is based on the latest Java 7 - or, at least, one which has the HTML bug in it.
Now, I'm on a Mac, and Safara kept bugging me to upgrade to version 60, so I did it. I figured I'd at least get to share the pain - but since I build KoLmafia myself and did not upgrade the JDK - just the JRE - apparently I don't have to use it. I suppose I should update my JDK to version 55, at least.