Is the Iberia site buggy when it comes to searching flights on Vueling?

I am flying from Barcelona to Split on 8/17 on the 11:45am flight... Its an Iberia flight operated by Vueling. Ideally I'd like to use my avios, however, if not, I could purchase the flight on the Iberia site (instead of the Vueling site), bc Iberia is now offering 2x avios on Vueling.

Today when I try to search from BCN to SPU, SPU doesn't come up as an available airport. Yesterday SPU was coming up. I searched booking as a revenue, avios ticket and even one world partner ticket, and nothing. Anyone know the trick to this?