Mail addressing works differently using the R6 client

We are using an R6.5 server with an extended directory (included in the directory assistance set-up) that contains three (sample) entries of:

Jamie Fender/Acme/Com

Jamie Jack/Acme/Com

Jamie Talyor/Acme/Com

In R5 and R6.5 client location documents, type ahead is enabled per character and both are set to look up all address books.

In the R5 client, create a memo and in the To: field type “Jamie” and it returns “Jamie Fender”. Type “Jamie T” and it returns “Jamie Taylor”, the correct user (so I deduce the server is working correctly).

However in the R6.5 client typing “Jamie” returns “Jamie Jack” and typing “Jamie T” can’t find anything.

NB. In R5 client typing “Taylor” and pressing F9 brings up a list of valid "Taylor"s. In R6.5 typing “Taylor J” presents “Taylor Jamie”.

Anyone know if there has been a change made to the R6.5 client to amend the name look ups? Is there a setting somewhere to make it work the same as in R5?