Got a bit closer to the issue i think: if i create a new mission, the S530F is listed in the warehouse(SP and MP both work).
But editing my existing mission it is missing and not listed.
Attached 2 screenshots: orig.png is from my mission and new.png is the standalone test mission warehouse, added a trk from the original MP mission as well for completeness.
So it seems existing mission files are not updating with new weapons in the warehouses. might be a more general issue.
New mission Warehouse:
Existing mission Warehouse:
server-20230126-193317.trk