Given this valid query:

with 
  a(a) as (select 1),
  b(b) as (select a from a)
select * from b;

I'm getting an error:

"Column ""A"" not found [42122-212]"

The problem can be worked around by aliasing a in the CTE directly, so this works:

with 
  a(a) as (select 1 as a),
  b(b) as (select a from a)
select * from b;

Producing:

|B  |
|---|
|1  |

A side effect of the above bug (or it's an independent bug?) may be that this query also doesn't work:

with 
  a(a) as (select 1),
  b(b) as (select a from a)
select b from b;

The error is now:

Column "B" not found

Maybe, this error is just shadowing the original one?