There is a fairly major bug in 4.1.7 that causes HTML tags to be stripped from posts. An example of this is that no matter what formatting you place in the editor of a page, post, or anything else, it is stripped on save or preview. This even affects the text only version of the editor. I expect that this has something to do with sanitising input, but it’s going a bit too far in this case.
I disabled all plugins on my site, and everything returned to normal. I then activated them one by one, and all was well until I activated AnsPress where the problem reappeared. I activated all plugins, and the issue persisted. I disabled AnsPress and the problem went away. As an indication, the below is that’s taking place.
With AnsPress disabled
With AnsPress enabled
Again, I think that this is due to HTML tags being stripped for sanitisation – I understand why, but this really needs to be looked at as it impacts the entire site.