Firefox 45.4.0 can't load many pages without unstable nss

[hfk22]

At the moment, my copy of Firefox 45.4.0, which is the current stable port for Firefox, can't load pages like google.com or yahoo.com when using the current stable version of nss, dev-libs/nss-3.23. Also, some pages like slashdot.org may load, but look really strange as though the entire page isn't rendering. This occurs both when running normally as well as in safe mode. However, if I upgrade nss to the most current unstable package, dev-libs/nss-3.27.1, everything works normal and as expected. Does anyone have an idea as to why?