email address and variables

ross_cartledge ,

you get through all items which have been changed and for each of those, you append the e-mail, means which each loop another or the same e-mail will be added.
One option would be to get the items and then filter the e-mail addresses (first select statement, my people picker column is named 'Person').
Afterwards remove any duplicate (union expression within the compose action) and perform whatever you like with the distinct values you get in return.
See below screenshot for your reference.
I have added an additional Apply to each action to filter for the related items of each person (@equals(item()?['Person/Email'], items('Apply_to_each')?['mailAddys']))
, as the point in time might come, your audience is asking for more details about the items they are supposed to have a look at 😉)