Here is an example of the problem:
I have HTTPS Everywhere installed if that may be doing anything.
Until HTTPS Everywhere is updated (looks like Nick's changes were merged in, so hopefully soon), the only thing to do is either avoid child metas or disable the addon. (I don't use it myself, so not sure if it's possible to set up an exclusion for meta.*.stackexchange.com.)
HTTPS Everywhere merged my fix for this in about a month ago, so no one should be seeing this anymore. If you are: stop blocking plugin updates!