When standing up drp_pipe for RFC-775, I (JFB) decided to leave redirecting pipeline stubs in pipe_tasks and obs_subaru, in the hopes of providing a more gentle transition. But we didn't (and still don't) have a way to mark pipelines as deprecated, and as a result a lot of users (including important ones, like PanDA developers and NAOJ production operators) found and used those stubs instead of better-suited pipelines in drp_pipe.
And since those stubs weren't (at least for the most part) being tested, anywhere, they were easy to break, and were recently broken on
DM-35551, causing one of two issues that torpedoed the w_2022_29 build. I'm not quite sure what happened, but I think it's past time to just remove these and force all code depending on them to be updated, even if that's disruptive; at present there's a good chance any such code is unwittingly using suboptimal configurations already.