Probably something to do with the entry in your library. I tried with various styles in a footnote and all appears OK.
Presume this is a corporate Author name? First check your Author terms list. Tools > Open Terms List > Author Terms List. Check the entry is correct and remove any duplicate entries here.
Open the reference in the library and delete the Author name entry, start re-typing. EndNote should auto suggest the entry from the terms list. Accept this and save. Go back to your document, make sure you have it backed up safely, unformat the citations and then update citations to see if the issue is corrected. If any miss-match citations appear, use the miss-match window to insert the correct reference(s).