When writing the pages of a document in the PAGES field in the type JOURNAL ARTICLE, EndNote changes the number adding a digit… (I know that the examples I give are strange, but it is as exactly as I need it to be!).
Please, see the example bellow:
. I write: 1676-(2) to 1676-(137) and it changes to the following: 1676-(1672)-1676-(1137);
. or L 183 to 51-L 183/57 and it changes to L 183/151-L 183/157
Have your tried changing the style “page numbers” option? see image.
If that doesn’t work (for example you do not want to apply the auto-change to the pages in other records), you could create a custom field and copy the pages field for the affected references to the custom field and delete the info from the pages field and add the custom field to the bibliography template. Make sure you have the | (separation) and “link adjacent” (represented by asterisks below) to prevent extra punctuation and spaces from appearing.
for an example (for Journal template, you would have to do this for each template that has that kind of page requriement).