I'm telling that because in my case I found I strange behavior with projected edges, when I change a past sketch in the timeline, the offset is maintained and everything is in fact fully constrained, but the geometry created from the offset turn in blue and does not remain black to show that it still fully constrained, it just a matter of mind blow in my case, I lost an hour to figure it out how to fully constrain the offset, when it was already, and probably is just a visual bug.
These are the steps to reproduce:
1. create a sketch
2. in the sketch create a rectangle fully constrained in the space, and give some dimension constraints
3. extrude the rectangle and create a body
4. create a new sketch on the top surface of the body
5. project the edges of the rectangle from the bottom sketch to the new sketch
6. create an offset from the the projected rectangle to the inside
7. check that the derived offset rectangle is black, so fully constrained
8. extrude the offset rectangle and cut down to create a box
9. go back and edit the first sketch and change the dimensions of the rectangle
10. open in edit the next sketch where the offset is
at step 10 you will see the rectangle generated by the offset has lost the black color, and become blue as it is not fully constrained when it fact it is, or am I missing something I don't know?
If I edit the offset value, the rectangle become black again, even if I set the same value.