unsupported boolean operator in join condition: `is not null and bool`

A error is thrown if join condition has expression: ... on t1.a is not null and t1.a < t2.b

        select * from (select "nb" as a from "null_t") as t1
        left join (select "nc" as b from "null_t") as t2
        on (t2.b < 3) and (t1.a is not null)

Sbroad error:

Sbroad Error: unsupported operator: unsupported boolean operation