Incorrect parsing of explicit sibling maps

[RedCMD]

Describe the bug
explicit sibling maps are parsed as nested

To Reproduce

?
? abc

Expected behaviour
output should be two map nodes
first one should be null: null
2nd one abc: null
l+block-mapping states children must be indented further and siblings use the same indentation

Versions:

• Environment: VSCode 1.89
• yaml: 2.4.3

Additional context

---
!!map { #should be this
  ? !!null "null"
  : !!null "null",
  ? !!str "abc"
  : !!null "null",
}

[eemeli]

Confirming this as a bug.