Hmmm, I got LATAM black in mid-March. BA does not recognize the number as oneworld emerald with the typical problems. No advance seat reservation, no lounge access.
But maybe that's another problem I was denied entry at the BA galleries Lounge in Brussels although showing the digital card and being on a BA flight. In the boarding pass I had my BA number, but when entering the LATAM number 'the computer said NO'