Duplicate keys are not reported as errors

[dyj216]

Describe the bug
The validation of a yaml file doesn't report duplicates.

Version of yq: 4.44.5
Operating system: linux.
Installed via: docker and installed binary (from arch repo)

Input Yaml
Concise yaml document(s) (as simple as possible to show the bug, please keep it to 10 lines or less)
data1.yml:

duplicateKey: true
duplicateKey: false

Command
The command you ran:

yq 'true' data1.yml > /dev/null

Actual behavior

# there is no output generated

Expected behavior

# command output in shell is something similar:
Map keys must be unique at line 2, column 1