There is a bug in the conversion from .json to .conll, where many labels for token classifications are lost in translation. I discovered it when exporting NER labeled data as .conll from Label Studio.
Example to replicate
The same error happens when converting the exported JSON with the converter using my example_data.zip.
label-studio-converter export -i export_json.json -c label_studio_config.xml -o output_dir -f CONLL2003
The provided JSON export contains 3 "-hdmi" and 3 "-displayport" labels. The converted CONLL contains no "-displayport" label anymore.
Versions
label-studio: 1.8.2.post1
label-studio-converter: 0.0.57
macOS: 14.0