Well I think we need to see your code as I don't have that result.

Code:
Break On
Dim $Start, $Stop, $Timeout
'KiXtart version is: ' + @KiX ?
$Start = @TICKS
'Start time was: ' + $Start ?
'Will now try to map a bogus share that does not exist...' ?
  USE X: '\\BOGUS\NOTHERE'
'Error mapping drive was: ' + @ERROR + ' - ' +@SERROR ?
$Stop = @TICKS
$Timeout = ($Stop-$Start)
'Time out took ' + $Timeout ?


Produced this result for me.

Code:
KiXtart version is: 4.52 Release Candidate 2
Start time was: 506277843
Will now try to map a bogus share that does not exist...
Error mapping drive was: 1203 - No network provider accepted the given network path.
Time out took 2282

 
As you can see the timeout for me was under 3 seconds.
Maybe some other issues going on there.

But this was NOT done within a LOGON script, it was done from a system that was already logged on.