Validation fails on a preferred-citation object

[logological]

I'm using a GitHub Action with cff-validator@v4 to validate this CITATION.cff file using version 1.2.0 of the schema. This always fails with the following error:

field	message
cff["preferred-citation"]	referenced schema does not match

However, I can't spot any problem with the file, and another CFF validator, cffconvert, thinks the file is valid:

$ cffconvert --validate -i CITATION.cff 
Citation metadata are valid according to schema version 1.2.0.

I've tried removing or changing certain lines I think cff-validator might be choking on and rerunning cff-validator, but I wasn't able to isolate the problem. (The Action takes a long time to run and I couldn't figure out how to run the tool locally.) Is it possible there's a bug in cff-validator's processing of preferred-citation objects?

[logological]

One more data point: the yajsv validator also thinks my file is valid:

$ wget -q https://raw.githubusercontent.com/citation-file-format/citation-file-format/refs/heads/main/schema.json
$ cp CITATION.cff CITATION.cff.yaml
$ yajsv -s cff.json CITATION.cff.yaml
CITATION.cff.yaml: pass