Regardless of how you get your references into your EndNote Library, it is important that you check your references in your library. Look out for:
Any mistakes in EndNote will mean a mistake in your Word document. If you do notice a mistake, edit the record in your EndNote Library.
Remember, you should only have one ENL. In order to manage your references, you can organise them into 'groups' and 'group sets'. You can do this manually, or set up criteria for EndNote to do it automatically. See Section 5.0 Managing your EndNote Library:
*New* for EndNote 21, you can also use the 'tagging' feature:
Remember the EndNote toolbar in Word is 'talking' to your ENL. If you are inserting the same reference/citation more than once, you need to make sure that you are telling Word to insert the same reference from your ENL, not a different record with the same bibliographic details. If you do insert different records, Word will think these are different references and start adding alphabetic characters to differentiate them e.g. (Kelly, 2024a) (Kelly, 2024b) etc.
To make sure it doesn't do this, you need to deduplicate your ENL regularly. See:
(5.4 Deleting duplicate records)