Did something change with Facebook in the privacy settings?

So for the last 2 or 3 weeks, I’ve noticed people that I know, who are not friends (on Facebook or in real life) replying to stuff and liking stuff on my friend’s Facebook postings.

These people don’t know each other and are not friends with each other.

What I reply to or like on Mary’s Facebook should not be visible to my Aunt June, but Aunt June and cousin Eddie are now replying to and liking all sorts of stuff posted by my friends, of whom they don’t know and are not friends with online.

I have my own privacy settings as such, that if I’m posting my own picture of my friend Alice (or something else related to Alice), my Aunt June and my cousin Eddie should not be able to see it, because I have not listed them as people who can see it. Why then, are they seeing stuff that Alice has posted that I liked or responded to and how do I change this?

Is everybody in my friends list seeing every single thing I like or reply to now, even though in my own settings, I limit every single post I make to be visible to just the people involved?

I’m also seeing all sorts of random stuff from my friend’s friends, people that I don’t know and am not friends with, because one of my friends liked something.

I don’t like the idea of everybody seeing every single thing I like or respond to. It didn’t use to be like this until several weeks ago. What has changed and how can I fix this?