[aprssig] What causes "Con" (Connect) LED to come on and stay on?

[Amateur Radio WB8NUT]

I have a Kantronics KPC3+ connected to a PC running Windoz XP.  I use 
AGWPE as the primary interface to the TNC.  I have used WinAPRS, UI-View 
and AGWTracker.  Several times a day, the "Con" (Connect) LED on the TNC 
will come on and stay on.  The only way to get it to go off is to turn 
off the TNC and turn it back on.  When in this condition, the TNC will 
still receive APRS packets and display them o.k. on any of the APRS 
programs, but it cannot beacon until the "Con" LED goes off via a hard 
reset of the TNC.  The TNC is running in XKISS mode with AGWPE.  It 
happens more with AGWTracker than the other programs, but it happens 
with all the programs.  I set the TNC up so that no connects are 
allowed.  This situation happens when the TNC is connected directly to 
UI-View or WinARPS without using AGWPE.  It also happens with another 
Kantronics KPC3 (not plus) model.  Kantronics does not know why this 
happens.  Anyone else ever experience this and can tell me what causes 
it and how to avoid the condition?

Thanks and Merry Christmas!

Duffy
www.wb8nut.com