"Už" is an impressively flexible inconstant clitic. When it is used as a clitic, it can go in the fringe of the clitic cluster (its end), or it can go all the way in the beginning of the cluster. The mid-cluster positions are more unpredictable.
Would you like to read more about this? Be warned: https://forum.duolingo.com/comment/38369227.
I put in we were already here.. was accepted as an alternative to we have already been here. But I don't think both sentences mean the same thing... whereas .. we were already here .... could be colloquial for we had already been here. so my question is if we had already been here is also an alternative answer.
There is no audible difference in Czech, it is a purely orthographical difference. The right course of action is to report these sentences so that the audio exercise is disabled.
What actually happened that the introduction of the new voice re-enabled all those exercises and we had no free time to go through all of them again. Bugger.