I had dozens of non-mainline AA (or US) flights lsat year, both pre- and post-integration. All posted their Avios quite fast (to IB+, though) except for a single booking in July where neither the outbound nor the inbound posted (but I claimed them online and it worked).

In fact, in December I had the opposite issue: two flights booked in O class gave me 50% Avios (or rather the minimum 250 Avios) rather than 25% (150) as they should.