Issues with multiple citations of an author and biblatex-apa
Recently I had to refer an author multiple times in a document. I had recently shifted to biber and biblatex. The American Psychological Association (APA) style was the recommended style.
And in the final references
The author name was, let us, was Wilbur-Markus Rowland, and he had about 10-11 articles. The author had many co-authors, in some cases this author was the first author in other cases he was the second or even third one.
Now the issue that I was facing was this: The same author name was getting cited differently at different places.
For example, in some cases it appeared like
W.-M. Rowland, in other cases Wilbur-Markus Rowland, and in some cases even as Rowland. This was very confusing. And on top of all that the final references had entries like
Rowland W.-M. (W. M.)
Rowland W.-M. (Wilbur-Markus)
Rowland W. M. (Wilbur-Markus)
Rowland W. M. (W.-M.)
I checked and rechecked the bibtex entries in hope of finding some error but it was not to be found. I must have done a Clean All a dozen times, after editing the bib file.. I tried adding same name entries for Rowland as first author to be the same, but it didn’t work. This was really frustrating.
Similarly a couple of references with two different authors with a common surname were giving intials in the main text. For example, D. R. Cook and M. P. Cook. Now all other refernces (except the Rowland one) were coming as per the APA requirement, which is (Author, Year), so ideally they should have been (Cook & Weston, 1999) and (Cook, 2004). But rather they were being displayed as (D. R. Cook & Weston, 1999) and (M. P. Cook, 2004). Now no change in the bib file was changing any of this. I thought there was some issue with the bib entries. I deleted the entries and entered them again manually, but no avail.
Then I chanced upon this link

 even though the year of publication differs in the two Campbell (Cook in our case) references, the lead author’s initials should be included in all text citations, regardless of how often they appear.

So the Cook mystery was solved. biblatex was compiling correctly as per the APA guidelines, the initials for the two different Cook entries must be there. This is because

 Including the initials helps the reader avoid confusion within the text and locate the entry in the reference list.

Now for the Rowland entry, the next part of the blog gave me a hint towards the possible problem:

Although this rule seems straightforward, one thing that trips up some writers is how to proceed when different lead authors with the same surname are also listed in other references in which they are not the lead author.

After this I checked the entries where Rowland was second or third author. These entries differed from the entries where he was the lead author. And this was causing the problem. For each different entry style of his name, biblatex was considering him as a separate author. Hence the initials and the different references entries with names in brackets. Once all the entries for Rowland were made consistent the problem disappeared. Phew!
This issue bugged me for almost a couple of working days, to find the cause and subsequent addressing was most rewarding.
Note that the bibtex references that I had were taken from google scholar, hence differing styles in author name. Please make them consistent. This is a warning for future me and others who are reading this post.