This is very frustrating as I've had this working - but now it isn't and i'm not sure if it's user error (probably) or something else.
I have created one line of text and tried to apply the Text Tracking behaviour. Instead of stretching out from the centre of the text (as the effect preview shows) my text stretches out from left to right: ie the left hand letter doesn't move at all with the furthermost right hand letter in the sentence moving most.
I assumed this was an anchor point issue, with the effect anchored to the left hand side of the text box and so moved the anchor point of the text layer to the center. However, that doesn't seem to make any difference.
I'm using the anchor tool within the canvas, but to no avail. I have also tried setting anchor points using the inspector - same (lack of) results. I've tried moving the anchor for the layer and also for the group, nothing works.
I have created a line of text in a previous project that applied text tracking in the way I want, so I know Motion 5 is capable, but for the life of me I can't get it to work now.
I know I may well be missing something very obvious.