I think there is a problem with the plural that provides the extra letter. The preamble to Chambers provides its rules for plurals which state that unless specifically indicated, plural nouns are formed by adding an S or ES at the end. So for almost all nouns no plural is given. When a noun differs from that convention, its plural is given. Thus, for the team that comes in second,
the plural is there in bold. The same for your spouse's mother or father or sibling. But this entry is NOT in Chambers in plural form.
However, I have no doubt it is what is to be entered. TEA has it, by the way.
Is anyone aware of a different noun like this one where the plural is not specified in Chambers?