Citation generator is inaccurate
The citation in the existing and new UI for books is not valid MLA or APA.
The PNX information that populates the citations is stored in a hidden mapping table that cannot be edited. For example, I can see that series information for a book comes from addata/seriestitle. Primo will use the entirety of the field in the citation. For this particular record, this is the content of that section:
Rowling, J. K. Harry Potter Ser. ; 2.
Likewise, book titles come from addata/btitle. For this record, this is the entirety of the section:
Harry Potter and the Chamber of Secrets / by J.K. Rowling ; illustrations by Mary GrandPré.
Because the content of the citation is based on fields in your records, you might want to examine your normalization rules for the addata section and see which fields from your source record are being used. Since you're seeing extraneous information in the citations, this might require changes to your source data or to the normalization rules (to pull data from a different source field).
If you want to change which PNX fields Primo uses to build the citation (for instance, changing from addata/btitle to display/title) this would qualify as an enhancement.