It appears that in one example a Scrivener.Page struct is being passed to update_status and, in the other, single integers rather than the expected List of integers. But, to @dimitarvp 's point, inspecting the query with his example code will likely uncover the issue quickly. Additionally, IO.inspect can help a lot in debugging.

For instance, it could be added to update_status…

def update_status(ids) do
  IO.inspect(ids)

  Myschema
  |> where([a], a.id in ^ids and a.status == "PENDING")
  |> Repo.update_all(set: [status: "READ"])
end

It can also be added anywhere within a pipeline and multiple times…

def slogs(search_params, page, size) do
  MySchema
  |> handle_report_filter(search_params)
  |> order_by(desc: :status)
  |> compose_report_select()
  |> Repo.paginate(page: page, page_size: size)
  |> IO.inspect()
  |> update_status()
end

Exercise the code in your tests or even the running app and the inspected values will appear in the terminal.