Piglins get angry when opening your own chest even when not in a bastion

Piglins become angry when you open your own chest unless they are completely not able to see.
Happened in, I think 20w17a, but I was not able to select that for the version...
Occurs at about 00:35
https://www.youtube.com/watch?v=IeOz2r1WyqU&t=0s