SIMPLE Automation not working if row added at the bottom

Hi, I have a very simple automation that is not working and can't figure it out.

Trigger: When rows are added

When: Any field

Run workflow: When triggered

Action: Assign people

Assign people in "Managers" (I have 2 contacts)

In a sheet, if I add any data in any column on a row at the very botton it doesn't work! If I insert a row elsewhere in the sheet and add data it works!

What is the issue with adding at the bottom of the sheet?

I'm stumped, thanks!