This is because APA requires disambiguation of same surname authors who are different. So K Burke and J Burke would need to be distinguished in the citation.
However, endnote is not very good at figuring out that Burke, K. and Burke, Kieth or sometimes even Burke, K. and K Burke are the same author. The best way to avoid this, is to open the references with K Burke in them and copy from one record, replacing the other K equivalent authors.
This is explained in a more detail, but back to front (That is, the usual cause and fix is in the last two paragraphs), here: https://support.clarivate.com/Endnote/s/article/EndNote-Removing-author-name-initials-from-APA-Style?language=en_US
If you want to override this - you can change the output style instead, but then you run the risk of not conforming to the requirments of the publisher were there are two different authors with the same surname. (here is one set of instructions to do so: http://libguides.usd.edu/content.php?pid=63203&sid=5661477)