Prisma: Model with three unique index fields referencing optional fields

I got a question regarding unique indexes with optional values. I have a schema like this:

model Thread {
  id               Int            @id @default(autoincrement())
  createdAt        DateTime       @default(now())
  updatedAt        DateTime       @updatedAt
  body             String
  user             User           @relation(fields: [userId], references: [id])
  userId           Int
  likes            Like[]         @relation("ThreadsOnLikes")
}

model Like {
  id        Int      @id @default(autoincrement())
  createdAt DateTime @default(now())
  user      User     @relation(fields: [userId], references: [id])
  userId    Int
  thread    Thread?   @relation("ThreadsOnLikes", fields: [threadId], references: [id])
  threadId  Int?
  comment   Comment? @relation("CommentsOnLikes", fields: [commentId], references: [id])
  commentId Int?

  @@unique([userId, threadId, commentId])
}

And inside a resolver I want to for example delete a like from a user for a specific threadId like so:

await db.thread.update({
    where: { id: input.id },
    data: {
      likes: {
        delete: {
          userId_threadId_commentId: { userId: session.userId, threadId: input.id },
        },
      }
    }
  })

But when I try to execute that mutation, prisma throws the following error: Argument commentId for data.likes.delete.userId_threadId_commentId.commentId is missing. When I add it to the delete argument with , commentId: null it states this error: Argument commentId: Got invalid value null on prisma.updateOneThread. Provided null, expected Int. Although inside the database the comment_id field is actually null . Is this a bug or how is this fixable?

From the docs:

All fields that make up the unique constraint must be mandatory fields. The following model is not valid because id could be null:

model User {
  firstname Int
  lastname  Int
  id        Int?

  @@unique([firstname, lastname, id])
}

The reason for this behavior is that all connectors consider null values to be distinct, which means that two rows that look identical are considered unique:

 firstname  | lastname | id
 -----------+----------+------
 John       | Smith    | null
 John       | Smith    | null

I am not sure why Prisma is unable to validate schema beforehand in "compile time", maybe it is a bug, so I suggest you to maybe create an issue on Github?