Not that it has much to do with the upgrade but I have run into a similar issue in the past. In our case, the ACD in question was connected to the CMS by a cross-over ethernet cable from the CLAN (the other ACDs were over the company ethernet). They used a cross-over connector and a piece of CAT-3 cable on the back of the CMS machine to convert our normal CAT-5 to a cross-over (Avaya indicated that this is very common). The tech I spoke with had me replace the cables and connector with a single CAT-5 cross-over cable and it resolved the issue for us. Not sure if this will help or not, but there it is.