As demonstrated here, PlayerInteractEvents fire when left-clicking the zombie on the right (without blocks behind). When left-clicking the zombie on the left (with a stone block behind them) no events are fired at all where I would expect them to be fired. I think this is because in this scenario I am too far from the zombie to attack them, but close enough to be able to target the block behind if the zombie wasn't in the way. If I move further back, to where I couldn't target the block any more, events would start firing again.

Attachment given in streamable and mp4 format in case the mp4 format doesn't work, as well as a tiny plugin to test it if needed. the plugin also gives instructions when someone joins the server

https://streamable.com/egrkvq