Update, fyi, no action needed:
I rolled back to IE 10, then 9, then 8. all to no avail.
1) I started by doing a full uninstall of ArcGIS from machine and reloading 10.1. the original problem persisted.
2) I cleaned that installation and installed 10.2. problem persists.
3) I upgraded from IE 8 to 11, installed IE SP, and problem persists.
4) I�??ll keep using the script I wrote which calls the command, and works fine. I�??ll keep a log of crashes/errors.