Materialization is lost from subquery CTEs

[freddiescadding-pennylane]

We have found a scenario in which a CTE's materialization is lost in the resulting SQL:

When defining using .with.materialized(...) within a UNION ALL subquery, the CTE is ultimately defined without the MATERIALIZED keyword.

User
  .union_all(User.with.materialized(highly_liked: ProfileL.where("likes > 300")))
  .union_all(User.with(barely_liked: ProfileL.where("likes < 100")))

=>

WITH 
  "highly_liked" AS (SELECT "profile_ls".* FROM "profile_ls" WHERE (likes > 300)), 
  "barely_liked" AS (SELECT "profile_ls".* FROM "profile_ls" WHERE (likes < 100)) 
SELECT 
  "users".* 
  FROM (...)

When defining the CTEs at the top level, however, it works as expected:

User
  .with.materialized(highly_liked: ProfileL.where("likes > 300"))
  .with(barely_liked: ProfileL.where("likes < 100"))
  .union_all(...)
  .union_all(...)

=>

WITH 
  "highly_liked" AS MATERIALIZED (SELECT "profile_ls".* FROM "profile_ls" WHERE (likes > 300)), 
  "barely_liked" AS (SELECT "profile_ls".* FROM "profile_ls" WHERE (likes < 100)) 
SELECT 
  "users".* 
  FROM (...)

Is this expected behaviour? I have seen your comment on piping, but I don't think it applies to this particular example.

Many thanks

[freddiescadding-pennylane]

@GeorgeKaraszi Please can you let me know if this is expected behaviour, and if not then whether a fix might be included in a future release? Thanks