Consistent journal abbreviations

I am having a problem with journal abbreviations in my bibliography.

I have updated the Term List and Journal, Abbreviation 1, and Abbreviation 2 are filled in for every journal.

However, in my bibliography, some references are abbreviated correctly, and others still show as the full journal title. This will sometimes be for the same journal, so this is not due to the journal being missing from the Term List.

For example, in one reference, it will say:

Proceedings of the National Academy of Sciences of the United States of America

and for another, it will say:

Proc Natl Acad Sci U S A

Can anyone offer a solution?? This is driving me nuts!

Have you also changed your output style to use the terms list?  

this is probably the best thread to read to catch all the parameters.