I have started a brand new game and repaired my game. Other people on the official forums are having this issue. http://forums.thesims.com/en_US/discussion/comment/14525150#Comment_14525150
In this picture, ashes appeared right after the Sim drank the serum and fell asleep.
In this picture, ashes appeared after my Sim gave this Sim a serum. This is the second serum my Sim is giving this Sim.
@canelacaliente, all I can do now is second @crinrict's comment of "Weird". It never ceases to amaze me how some people can have a problem in certain situations and others not.
I'll continue to keep an eye out for the problem as I play my scientist in the current save and post if I encounter the issue. The only difference in style of play I could see from your pics is that I don't give the same coworker two serums in a row to drink. I always pick a different guinea pig for a second serum. Not sure that's relevant, though, as it looks like you got a pile of ashes from the first serum.
