Automatic Deletion of duplicate photos in an Album

I think you should note that duplicates are never "automatically deleted." You see them in a separate "Duplicates" folder that applies to the entire Library. Then you have to choose the duplicates and either merge them or delete them.

Suppose you have a picture "Granny at the Grand Canyon" that appears listed in two albums called Granny and Grand Canyon. (There's really just one picture file but it's listed in two albums.) And you may have a picture "Grand Canyon with Granny" that is a different picture file but exactly like the first one, that's listed in two albums, in Trips West and also in Granny. Then these two picture files will be listed a single time in Duplicates.

If you choose Merge, then one will be deleted from your Library, and the other will be included in all three album lists--only once in Granny.

If you choose "Grand Canyon with Granny" and delete it, then that picture will disappear from the albums Trips West and Granny and it will no longer be in your Library, but "Granny at the Grand Canyon" will continue in the albums Granny and Grand Canyon.

I hope that's easier to read than it was to write...

Duplicate photos are removed from the (main) photo library itself. Thus, they will be automatically removed from the albums using them.