I've got mixed thoughts.

The action on its own would normally be quite harmless. I fix my students shoes and things on a regular basis (I'm a big believer in making them have their hoods on and coats done up... they seem to think that -40C isn't that cold). I'm also the sort who will tuck people's tags in. I've also had a friend or so fix MY scarf for me. So the action itself can be quite innocent.

I think that it probably wasn't the healthiest thing in this situation. Growli, you are already viewing your T as being literally a mother for you. She's supposed to be helping you with becoming independent, but this action of hers, regardless of how innocent and funny it seemed, was really reinforcing your dependence on her. She could have asked you to tie your own shoes - which would have been appropriate and more like an appropriate caretaker should be doing.

Do you feel more attached to T and wishing even more that she could be your mom? Or are you feeling like you would have rather sorted out your shoes yourself? I think that if it reinforced your desire to replace your mom with your T, then it was not a healthy or good interaction. If you felt awkward about it and would have rather sorted it out yourself, then it could be a good interaction because it could be reminding you that you are capable of taking care of yourself on your own.