Turns out I have two plugins given the order to display featured images for my WordPress site
It was supposed to be one. The latest plugin I installed came with an action to insert featured images. So, all I did was to deactivate feature in the recent on I installed
I noticed this but inspecting my feed, I noticed the images were replicated
And they weren't so before
So I traced the recent changes I made on the website
Trial and error
Luckily I found the issue soon