There was some amendment to the budget due to ISIL and other activities that made it, indeed, 21B in 2017.
I'm not seeing the trend you assert. It looks like it doubled from 2001 to 2016. That's not perfect, but its not really bad either.
I don't know how this compares to other functions, and whether the state department has gained or shed responsibilities.
If you are looking for outrageous waste, then I would argue that if any happened in state, it happened in the last two years.