Wrong predicates generated on union types

[Andy2003]

given the schema:

type A @node {
    id: ID!
}
type B @node {
    id: ID!
}
union Base = A | B
type Test @node {
    id: ID!
    bases: [Base!]! @relationship(type: "HAS", direction: OUT)
}

I would expect different results for the following requests:

SINGLE

request

{
  tests(where: {bases_SINGLE: {A: {id: "1"}, B: {id: "1"}}}) {
    id
  }
}

actual result

MATCH (v0:Test)
WHERE (single(v1 IN [(v0)-[:HAS]->(v2:A)
  WHERE v2.id = $p0 | 1]
  WHERE true)
  AND single(v3 IN [(v0)-[:HAS]->(v2:B)
  WHERE v2.id = $p1 | 1]
  WHERE true))
RETURN v0 {
  .id
} AS v4

expected result

MATCH (v0:Test)
WHERE (single(v1 IN [(v0)-[:HAS]->(v2:A)
  WHERE v2.id = $p0 | 1]
  WHERE true)
  XOR single(v1 IN [(v0)-[:HAS]->(v2:B)
  WHERE v2.id = $p1 | 1]
  WHERE true))
RETURN v0 {
  .id
} AS v3

diff

SOME

request

{
  tests(where: {bases_SOME: {A: {id: "1"}, B: {id: "1"}}}) {
    id
  }
}

actual result

MATCH (v0:Test)
WHERE (EXISTS {
    MATCH (v0)-[:HAS]->(v1:A)
    WHERE v1.id = $p0
  }
  AND EXISTS {
    MATCH (v0)-[:HAS]->(v1:B)
    WHERE v1.id = $p1
  })
RETURN v0 {
  .id
} AS v2

expected result

MATCH (v0:Test)
WHERE (EXISTS {
    MATCH (v0)-[:HAS]->(v1:A)
    WHERE v1.id = $p0
  }
  OR EXISTS {
    MATCH (v0)-[:HAS]->(v1:B)
    WHERE v1.id = $p1
  })
RETURN v0 {
  .id
} AS v2

diff

---

Node: The diffs are from neo4j-graphql-java, so the left side is the js cypher and the right side is the java one. Top is the normalized version bottom the original.

[neo4j-team-graphql]

We've been able to confirm this bug using the steps to reproduce that you provided - many thanks @Andy2003! 🙏 We will now prioritise the bug and address it appropriately.