I just assumed the entire FAANG group scanned user content for CP already. I mean, EU recently passed a vote that extended the permission for companies to be able to scan and report user content for this purpose without it being considered a privacy violation [1] (first introduced in 2020). And I recall MS[2]/Google[3] being open about this practice way in the past.
Personally I somehow doubt that MS/Google weren't scanning private content (aka not shared) for this type of material. But can't have transparency with these behemoths.