I am afraid I do not have enough evidence to formulate a solid hypothesis for either question. [Which is worrying - without those answers, they haven't exactly fixed the problem, have they.] Were I to hazard a guess, I would say that the wards being fully recharged dispelled the illusion; as to the displayed keystones...either impacts on the other side of the wall from attacking demons, or...sabotage. The latter is more likely.

[The fully charged wards are repelling their teammates who are demonic in nature; surely they would repel this world's demons as well, which makes an initial attack unlikely at best.]