Hey /u/OwlcatStarrok thanks for the updates - I appeciate you must be getting hammered with questions at the moment.
Do you know when in Act2 the threshold is for when it would be safe/unsafe to respec? There is a big difference between "any time in Act2" and "After you have locked in your Mythic path"
Thanks :)
Seems to be the Siege of Drezen. If you do it prior, you should be fine. Also, a fresh update from the tech team - seems that Legend isn't affected after all.