If you look at the \Program Files (x86)\LANDesk\LDClient\Data\SDClient_Task###.log for that task, and look for the line that says "Processing Generic Executable" does it have the switch that it is supposed to run with? Let me know.
Yes, the switch is there:
Mon, 22 Sep 2014 15:53:12 Processing generic executable
Mon, 22 Sep 2014 15:53:13 Launched application 'C:\<path>\<Executable>' ('/silent') result 0
The task also gets listed in the Local Scheduler tasks once I hit snooze and the command line switch is listed in there with a cmds="/Silent" argument.
I am seeing this behavior in both our LANDesk 9.5 SP1 production box and our 9.5 SP2 Lab environment so I have opened a case with LANDesk support to try to get to the bottom of it.
LANDesk support has sent this to their engineers for remediation. I am now looking at the Patch management module as an alternative.