I was slowly logging my way through `content/bower` -- would have taken a while to find the issue. Shoulda been looking on github instead. ;)
I'll apply the fix locally while I'm testing my updates and hold off on updating production until the next release -- it's already going to be a harry update from v0.6.0 / v2.2.5 to v0.10.1 / v4.3.0.
Thanks again for your help!