All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The basic ruling regarding an oath is that it is invalidated after breaking it for the first time, so the expiation is not repeated unless you intended to repeat breaking the oath when you swore, or there was an expression in the wording of the oath which implies repetition, such as the word 'whenever'.
Ibn Juzay said in Al-Qawaneen al-Fiqhiyyah: “The breaking is not repeated by repeating the act, except when the wording of the oath implies repetition, such as saying 'whenever', 'when', or similar words, or if the oath is made with the intention to repeat breaking it.”
Allah knows best.