To provide context, the crash occurred in the middle of the third Spring for the fort. It happened as I was placing a traction bench in the hospital of my "starter fort". As that was happening my dwarves were also caging excess cats and pasturing a sloth I bought from the Elf merchants. The only other thing that had just happened was I received a sizable migrant wave. The crash took me back to the start of Spring, and I tried placing the the traction bench again, at the start of the Spring season, but wasn't able to reproduce the crash.