This search: https://meta.wikimedia.org/wiki/Special:Search?search=Hasty&prefix=Research%3ANewsletter%2F20

should return this page: https://meta.wikimedia.org/wiki/Research:Newsletter/2015/March#cite_note-17

which contains the search string as part of a template:

{{Cite journal| [...] | last1 = Hasty| first1 = Robert T.| last2 = Garbalosa| first2 = Ryan C.| [...] }}

The other author names in that citation seems to have the same problem.

On the other hand, the problem doesn't seem to be the template itself, as other uses of the same template show up just fine in search results (example).

@EBernhardson observed on IRC:
"fwiw it looks to have been removed somewhere in the indexing, because it's in the source_text field and not the text field. [...] https://meta.wikimedia.org/wiki/Research:Newsletter/2015/March?action=cirrusdump
[...]
for now you can find it with this, but it doesn't do stemming so you wont find hastily when searching for hasty: https://meta.wikimedia.org/w/index.php?title=Special%3ASearch&profile=default&search=insource%3AHasty+prefix%3AResearch%3ANewsletter%2F20&fulltext=Search "

(Context: The archive search function of the Wikimedia Research Newsletter has become increasingly important as a way to quickly find coverage of academic research publications about Wikipedia from half a decade, so it would be great to fix this one way or another.)