On the NXT platform, the three on-board motors are enabled by default with Encoders and PID control "features" enabled.
When you set a NXT on-board motor to "No Motor" and then hit the apply button, ROBOTC will undo this action because it won't allow an NXT motor to be disabled. The GUI solution (and the bug) is then to simply turn the motor back on but disable the Encoder the PID Control fields.
The Motors and Sensor Setup Pragma configuration generator will not generate pragma statements when a motor is in it's default position (for NXT: Enabled/Encoder/PID Control), but because the previous action of setting the GUI to "No Motor" disabled the Encoder and the PID Control checkboxes, the Pragma generator recognizes this is different from the default configuration and generates a Pragma statement to recognize this new configuration.
It's a pretty innocuousness bug, so I doubt we'll be rushing 3.61 out just to fix it

- but, I'll add it to the development list for the next release/beta.
_________________Timothy Friez
ROBOTC Developer - SW Engineer
tfriez@robotc.net