With two or more authors APA should use the & symbol for bracketed references. The word “and” is used only if the authors names appear in the (non-bracketed) text.
Correct:
…(Baumeister & Vohs, 2007)…
…Baumeister and Vohs (2007)…
Incorrect:
…(Baumeister and Vohs, 2007)…
The add-on seems to be using the incorrect way here.
Please check: http://blog.apastyle.org/apastyle/2011/01/writing-in-text-citations-in-apa-style.html?_ga=1.177679077.1522928650.1474245137