Ive experienced the same thing repeatedly.
Basically all animation freezes but the game and bot continue going.
The bot is controlling the game, and you can even hear the sounds as it does what it is doing.
I verified that the game has not actually quit, and is not just looping sound, If you click "force town run" you will see the bot log as it ports to twon after it is no longer in combat, hear it salvage etc.
Not sure why diablo client is visually freezing up, But its only visually.
This leads me to believe its not an issue with demon buddy, unless the bot is somehow causing the graphic processing of the game to be frozen?
But to be honest, hard to tell.
Bot logs wont help im sure, because it will just show a log of what was happening in game etc, and technically the game and bot both are running.
Unless tony or someone can reproduce the effect to try to determine the issue, not sure what can be done. Not like we can submit a ticket to blizz..
"Hey, im having an issue with D3, its graphically freezing while my bot is farming for me.."
LOL
But be rest assured its not from you doing other things, etc..
I have had it happen with only the bot and demon buddy running.
Both with and without the blizz launcher open.
with webpage left open and also no browser open.
EDIT:
This doesnt occur at a specific amount of time lapsed for me.
I have come home from work with everything still going and movement on game screen.
and i have come home to a frozen appearance of diablo, while still hearing the sounds, and seeing the bot log showing the current operations .
For me it tends to seem to happen after a few hours of no interaction on my part with my computer/the game/the bot
EDIT #2
Only thing other than a few profiles added is, i use the Plugin EZUpdater. (just in case that makes a difference)