SOLVED!
The AmiTCP:bin/telser program was corrupted. Reinstalling using the supplied installer (multiple times even!) didn't fix it even with a complete wipe of the AmiTCP: directory first or a wipe and re-extract of the aminet 1.40 archive... but copying the file manually from the install folder to AmiTCP:bin/ worked. I used a combination of SnoopDOS and an AmiKit install of OS 3.9 to track it to this program.
I copied the program manually from the install directory to AmiTCP:bin/ directory and it immediately started working.
So I guess the question that lingers now is do I have a flakey Installer program, a flakey Installer script for telser 1.40, an even flakier A3K that I thought, or could a running patch/utility be wreaking minor bits of havoc on installations I'm running?
BTW, I was able to duplicate the issue on the AmiKit side as well so I'm leaning away from the A3K being an issue.
Insight would be welcomed.