GDS does not index all words

[infotainment]

Ever since I am using GDS, I have noted that it will not list files that contain a certain word I am looking for, although it will list other files that also contain the word. But the missing files are indexed; when looking for another word, the files are listed correctly. I already brought this to Google Support's attention, and all they told me was "just re-index everything," which I did, but it did not solve this issue. Right now, I am using the very newest GDS version, and the problem still persists. Has anybody come across the same (or similar) issue, and found a solution?