OK I found the video I saw when it was posted a while ago, can't remember how long ago, but anyways the video:

https://www.youtube.com/watch?v=RmaqGrmA6gs

And while searching, I came across these articles:

https://www.mamavation.com/food/kerrygold-pure-irish-butter-wrapper-pfas-forever-chemical-lab-results.html

https://www.greenmatters.com/food/kerrygold-butter-recall

https://www.classaction.org/news/kerrygold-pure-irish-butter-contains-forever-chemicals-class-action-alleges

EDIT: Forgot to mention that it wasn't heavy metals I was originally thinking of, but PFAS, or better known as "Forever Chemicals" found in Kerrygold.

OK I found the video I saw when it was posted a while ago, can't remember how long ago, but anyways the video:

https://www.youtube.com/watch?v=RmaqGrmA6gs

And while searching, I came across these articles:

https://www.mamavation.com/food/kerrygold-pure-irish-butter-wrapper-pfas-forever-chemical-lab-results.html

https://www.greenmatters.com/food/kerrygold-butter-recall

https://www.classaction.org/news/kerrygold-pure-irish-butter-contains-forever-chemicals-class-action-alleges