AOL email on safari different than AOL desktop

I have an AOL account but get to my email on AOL via Safari. It seems to work better and faster than using the Mac desktop AOL has. However, how come my email box on safari is different than my email box when I go to it from the AOL desktop?

In other words, my AOL email box via safari is more updated. When I go to my AOL email box via the AOL desktop...it seems that there are older emails in it that I've already read and even trashed when I saw them in safari.

Why does that happen?