When generating PDF from an article, <ref group="foo"> and <references group="foo"> are treated as if they were <ref> and <references>. For an article with a separate "notes" and "sources" section, that means that all notes and sources will appear in the "notes" section (assuming it comes first) and the "sources" section will be empty. Example: [[hu:1962]]
(I first wanted to report this to PediaPress, but the "upstream bug tracker" link in the extension description redirects to another page with no information about the bug tracker.)
Version: unspecified
Severity: minor