Technical questions regarding move tool in Adobe PS - triangle selection for X and Y values?

 When using the move tool (Command + T) to make repeat patterns, selecting the triangle on the task bar typically changes the X and Y values to zero. I have occasionally encountered what I think is a bug or a random setting that causes the numbers to randomize and the refuse to reset to zero. Has anyone encountered this, and do you know how to fix it? Also, does anyone know that this triangle button is called (silly question, I know). This has occurred on both a Mac and a PC. Thanks!