Paper A that cited Paper B is found via GoogleScholar, yet the citation is not counted for Paper B. Why? As stated in the subject, Paper A that cited Paper B is found via GoogleScholar (as is paper B), yet the citation is not counted for Paper B. Can anybody offer some insight into how this can happen or why?
Note that the paper B was properly cited by paper A, via a citation export on one of the popular services.

Is this common? I thank you in advance.
To determine that A cites B, Google Scholar parses the citation list at the end of paper A. There are a number of things that could go wrong there: bad OCR, use of ligatures in Latex, confusion between papers with the same title, a "references" section that Google does not identify as such...