I just noticed it (redownloaded theme) youtoube link in iframe is aligned to the left intead of being centered, I turned off all the plugins
I have two vaults, one with older version and one with latest, the older was ok until I updated
code
<iframe width="560" height="315" src="https://www.youtube.com/embed/--_K4G3HCcI" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>