The first time I have seen this flag...

"UN rights body adopts first resolution to protect rights of intersex people"

https://www.reuters.com/world/un-rights-body-adopts-first-resolution-protect-rights-intersex-people-2024-04-04/

"Intersex-Inclusive Progress Pride Flag at the Smithsonian"

https://www.cooperhewitt.org/2023/06/20/intersex-inclusive-progress-pride-flag-at-the-smithsonian/