Solution for this topic
I just realized it was actually my bad. I had already set a float value to the iframe element so the header ad would stay at the right side of the header.
The thing is that I ended up not being specific about it and it affected the videos as well.
Thank you so much for your help, and sorry about the inconvenient!
Of course, here it is:
It happens right in the beginning of the text and close to the end as well.