ETM S60 - Idle Issue after replacement and new software
 

I recently replace my ETM with a new replacement from a Volvo Dealer. I had to take my car in afterwards to have the software loaded to the ETM's ECU. The issue I'm having is as follows:
- High Idle when coming to a standstill after driving +/- 1500rpm and goes down to 850pm after about 5-10 seconds
- When it is at 850pm and car rolls forward in traffic and without touching the accellerator the revs go up again to about 1500rpm but if you return to standing position the idle returns to 850rpm.
This issue did not exist prior to changing the ETM - is it related to the software? or my main ECU requiring a possible software upgrade? or is this related to another issue?