The linked threads are pretty helpful if you only have one form. Ie, your bear has a consequence only the bear can have, it'll be there when you change back, may even need to be put in recovery while in bear form. so pick a consequence only the bear could have, that doesn't make sense for a human, and it's fine that it vanishes when you are human.
For True Shapeshift it is a lot messier. You could have lots of forms with 5 endurance, and a consequence that makes sense for a bear might not make sense for an elephant.
My solution was to essentially say that 5 endurance is a statement means you're using ectoplasm somehow to increase mass even if you don't go all the way to the 2 point Large power. So for me the extra consequence is tied into your ability to increase mass, it's damaged until that consequence is dealt with....your ectoplasmic extra mass always is missing a tail, or has a flap of skin hanging off or something, or the ectoplasm itches, consistent from form to form. It is likely tied deeply into the self-image of the shapeshifter until fixed, so it is a "tic". It isn't a perfect solution - I expect you'll need to really look at the actual character and decide what is best, from a flavor standpoint, to make the mechanics work where that extra consequence behaves as if it was an extra conditional stress box and not take you out of suspension of disbelief.