I switched the Launchpad daily builds over to Ubuntu 14.04 a few days ago in response to a dependency bump. However, now I see reproducible segfaults while building the docs:

reading sources... [ 63%] examples/pylab_examples/multipage_pdf
*** Error in `/usr/bin/python': double free or corruption (!prev): 0x0b8f0c78 ***
Segmentation fault

Example build log

There are also several warnings from mpl and numpy, but I think they're unrelated to the segfault.