Not sure if this is a bug or the way it is meant to work!
In my inbox (atm) when I click on the only email I have it indicates that I have 1 of 1 email - this is ok
In my archive box I have 12 emails but when I click on any of those it also indicates that I have 1 of 1 email - and when I click on 'older' (right hand side of heading row) this sends me back to the inbox, even although there is a 'back to inbox' button on the left hand side of the same row.