Is it a case where your server connect is running before your input is automatically populated with a value?
I had this problem as well. I solved it with a page flow and a wait. I have my serverconnect set to not autorun. With this page flow it waits a second and then runs the server connect. This gives the inputs/selects time to populate.
The ternary expression says that if NOT both param1 AND param2 are present, then add the noload property otherwise remove it and every change of a bound parameter will trigger the SC call.