The one and only thing that Beatty did wrong, to me, was to not just walk over and ask someone off stage. He was clearly confused and knew something was wrong. Better safe than sorry.
But that broadcast, in general, was really fucked up. The pre-taped videos, for example, kept ending before they were finished. That's live broadcast 101, to have those things perfectly timed to their segments. And then there was also the error in the In Memoriam.
I recently did a truck broadcast prep for the first time a few weeks back. We made all of the vignettes for the NHL 100 ceremony and I'll tell you what, the company that hired us was ON their shit about timings. The people who put on the Oscars have NO excuses for not having timings down to the second. Very strange, IMO.
Also it was really such an oddly low-budget affair. Having Kimmel host, having no introduction, very modest live performances, etc. They probably spent like a quarter of what they normally do on this production.