I entered a portal today and nothing had been killed (like previously when I'd done one, the mobs were dead and I caught up to the others as we made our way through). This one, nothing had been killed (or as I know now, had respawned). I fought my way to the end alone and figured I'd be soloing this one and was curious to do it alone; but when I got the the end, the boss fight ends as I walk up as others completed it. So I fought my way to the end for absolutely no reward i.e. no reason. Not sure these portals are worth the waste of time if it's going to be like this. Why bother working to get to the end if it could end without you and you get nothing. Something should be changed here, whether the portal mobs all stay dead and don't respawn so you know you are trying to 'catch up' to the fight, or make the instance solo, or end it as soon as boss is engaged so others can't waste time, or give the chest if you've killed any mobs working your way through. Not saying any of these is the perfect solution, but they are all better than wasting players time IMO. Much like the storms in skyrim when they first came out, I won't be wasting my time on these anymore.