I've changed the payee of a lot of transactions, relocating from PAYEE1 to PAYEE2.
After that, I've deleted the PAYEE1.
No problems till I saw into the register of "Repeating Transactions". All the transactions with PAYEE1 as payee have lost her payee and now the payee is blank!
I have to fix it manually but I sure that this is a bug: you should not be able to delete the payee if this is used in the future transactions too.