ServerNext performance issue

Hello,

we have a performance issue in an AX 2012 CU4 installation. I used the AX Trace Parser to track down the problem. The problem appears by jumping from CustTableListPage (select one customer per double click) to the CustTable form in linkActive (super()) method, if a special filter (Street name of customer) is set in the CustTableListPage. The Trace Parser shows the following:
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Database Time of Statement: 342 ms
ServerNext Exclusive 40264 ms

The Datebase Time is ok, but the Exclusive Time of ServerNext is very high.
What does that mean? Is that a communication problem between Client and AOS?

Regards, Dirk