Port from 4.2.6 to 5.1.2 - SMUX no longer RFC1227 compliant?

Hi All,
 
 We tried testing software normally running under net-snmp-4.2.6 under
5.1.2, and find that a SetRequest, which generates several PDUs to the
SMUX peer, no longer preserves the unique id. Instead it is incremented
for each PDU sent to the SMUX peer. This unfortunatly destroys the
transaction/rollback logic, as we cannot group SetRequests.
 
 * We cannot find any changes in CVS (smux.c) which warrents this
behaviour. Can you give us any pointers as to where to look?
 
 * Has anybody else seen this?
 
 Regards Jan
 
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From RFC1227:

3.1.5.  Request-ID

   When the SNMP agent constructs an SNMP GetRequest-PDU,
   GetNextRequest-PDU, or SetRequest-PDU, for a SMUX peer, the
   request_id field of the SNMP takes a special meaning: if an SNMP
   agent generates multiple PDUs for a SMUX peer, upon receipt of a
   single PDU from the network management station, then the request_id
   field of the PDUs sent to the SMUX peer must take the same value
   (which need bear no relationship to the value of the request_id field
   of the PDU originally received by the SNMP agent.)