I am having a similar issue. My APA 7 citation generator provides
Ellis, Franklin & Evans, Samuel. (1883). History of Lancaster County with Biographical Sketches of many of the Pioneers and Prominent Men. Everts & Peck. https://archive.org/details/historyoflancast02elli
I wouldn't call that a similar issue. You are basically getting APA with one error. Is that the same across items or specific to just this entry? How does the citation to this entry look?
It is an APA with one generally consistent error across multiple items I have checked. But there are some which are appropriately formatted.
Egle, William Henry (Ed.). (1890). Names of Foreigners who took the Oath of Allegiance to the Province and State of Pennsylvania 1727-1775 (Vol. 17). Harrisburg : State printer. http://archive.org/details/pennsylvaniaarch17linn
Diffenderffer, F. R. (1900). The German Immigration into Pennsylvania Through the Port of Philadelphia, 1700 to 1775: Vol. II The Redemptioners. The New Era Printing Company. https://archive.org/details/germanimmigratio00diffuoft
The inline citation (Ellis, Franklin & Evans, Samuel, 1883) is incorrect.
It's a data entry issue. You have "Ellis, Franklin" in a single field in Zotero (either just as lastname or in single field mode -- you'd be able to tell the latter by the two white rectangles next to the name). You should be able to correct that by toggling the field mode by clicking on said rectangle(s).
I'm not sure how that happened in the first place though. All the items import correctly from me from the Internet Archive.
Upgrade Storage
Ellis, Franklin & Evans, Samuel. (1883). History of Lancaster County with Biographical Sketches of many of the Pioneers and Prominent Men. Everts & Peck. https://archive.org/details/historyoflancast02elli
rather than
Ellis, F. & Evans, S. (1883). History of Lancaster County with Biographical Sketches of many of the Pioneers and Prominent Men. Everts & Peck. https://archive.org/details/historyoflancast02elli
Suggestions?
Egle, William Henry (Ed.). (1890). Names of Foreigners who took the Oath of Allegiance to the Province and State of Pennsylvania 1727-1775 (Vol. 17). Harrisburg : State printer. http://archive.org/details/pennsylvaniaarch17linn
Lancour, Harold. (1963). A Bibliography of Ship Passenger Lists 1538-1825 Being a Guide to Published Lists of Early Immigrants to North America (Wolfe, Richard J, Ed.; Third). New York Public Library. https://openlibrary.org/books/OL25127640M/A_bibliography_of_ship_passenger_lists_1538-1825
These, however, created appropriately formed APA bibliographic references
Kuhns, O. (2015). The German and Swiss, Settlements of Colonial, Pennsylvania A study of the So-Called Pennsylvania Dutch. Forgotten Books.
Curry, A. (2020). Ancient DNA tracks Vikings across Europe. Science, 369(6509), 1416–1417. https://doi.org/10.1126/SCIENCE.369.6510.1416
Diffenderffer, F. R. (1900). The German Immigration into Pennsylvania Through the Port of Philadelphia, 1700 to 1775: Vol. II The Redemptioners. The New Era Printing Company. https://archive.org/details/germanimmigratio00diffuoft
The inline citation (Ellis, Franklin & Evans, Samuel, 1883) is incorrect.
(Diffenderffer, 1900) but this one is ok
This issue is found in both v6 and beta 7.
What do I look for...why some and not others?
You should be able to correct that by toggling the field mode by clicking on said rectangle(s).
I'm not sure how that happened in the first place though. All the items import correctly from me from the Internet Archive.