Technically, you were enriched when you got the dividend. What you later did with the dividend is not relevant.

I think COR's point of view, is like if someone steals money from a bank, and then gives that money away to people on the street. Those people were not supposed to have that money, and the bank wants it back.

The problem here, is that most people didn't realize they were getting stolen money, and spent it, in good faith thinking that it was theirs.