Spotlight Searches on Mac

When I do a spotlight search on my Mac, it is often unsuccessful but I am able to locate that same file that I'm searching for by doing a Finder search. For example, I bought some light bulbs on Amazon and I saved the receipt pdf file on my Mac and named it "2018-10-05 Amazon $40". The pdf has been OCR'd so the text is searchable so I should be able to perform word searches on it by typing in some of the words in that file's name & contents (i.e. "2018", "bulb", "Amazon"). However, when I do a file search via Spotlight, the file is NOT found but a Finder search using the same keywords finds it. Additionally, I have an app installed on my Mac called Boxcryptor which encrypts all of my files but I did select "Enable Spotlight" in the app's preferences so Spotlight file searches are enabled. Spotlight searches previously worked well with Boxcryptor installed so I don't think this is the issue.