Track one is considered a soft master length. If you change the length of track 1 and all other tracks are the same length, it changes all of them to the same length. If even one of the tracks is a different length, we assume you wanted to do different lengths and only track 1 reset point is changed
And as others mentioned, hold a step button and hit reset to change the reset point of the track you have selected
Are these defined by how many notes you input in Lane one , or individual ?
Also
Can you change length after you have recorded ?