Is it penalty/ indexing issue?

I have created new blog ~12 months back. There are like 15-20 posts now and 5-6 of them are within top 3 (low competitive kws).


The problem is - One of the post which was ranking on 2nd position disappeared out of nowhere (not even in top 200), like 3 weeks back. I checked URL on Google and even the cache, the page looks fine. Even inspecting on Webmaster tools, it says the post is indexed. I checked the title with double quotes and even some part of content, it does't show any matches on Google! For other posts, it works fine and they are ranking within top 3.

I have checked backlinks and didn't found any links/ spam links. I am suspecting it could be possibly due to over-optimised content, but in that case, I have seen it come up with double quotes right?

Has anyone faced this before?

Could be you are lacking authority or could be penalty. You could try adding new content and create internal links, see if that works. Another thing could be due to over-optimisation, but I am not 100% sure about that.