We had the same problem at the o2 during the first show. The screens where acting odd until they switched them off for most of the first act. They blamed a generator problem. For us who were siting far in the back it was a real pain. the sound was strange also. We couldn't hear Mr. Jonas in One Day More (some like me would say that we couldn't hear him anyway during the whole show).
In my heart, I found the answered dream,
and in my soul I found the song, and in my friends
I found the magic, the love,
the moon up above- they were mine, all mine, all along..!