Problems processing citekeys for references without an author

[wilkohardenberg]

Explain the problem.
Pandoc 2.16.2 does not process correctly bibliographic references from Zotero (via Citeproc) that don't have an author.

Take for example this footnote:

[^tingle]: See @tingle. On this tool's limitations, see also @tingle2006. Another example of a sea level mapping tool with similar limitations is @zotero-30378. On the impact of the melting of all of Antarctica's ice cover on sea level, see @davies.

In 2.7.3, with this command

pandoc -s -o 7_Afterword_Tide.docx 7_Afterword_Tide.md --bibliography /Users/whardenberg/Dropbox/TempLibrary.bib --csl /Users/whardenberg/Zotero/styles/chicago-fullnote-bibliography.csl

it, correctly, produced this footnote:

In 2.16.2, with this amended command

pandoc -s -o 7_Afterword_Tide.docx 7_Afterword_Tide.md --bibliography /Users/whardenberg/Dropbox/TempLibrary.bib --citeproc --csl /Users/whardenberg/Zotero/styles/chicago-fullnote-bibliography.csl

it produces this:

The problem here is the comma after "limitations is" that shouldn't be there and didn't use to be there. Is there a way to get back producing footnotes that correctly parse citekeys?

Pandoc version?
2.6.12, macOS 10.14.6