Interesting - I was getting complaints about this same thing in UAW - and I thought it was my power settings, I had never heard of this in 4.0. I suspect it may be internet lag and the transmission of data between players, as I have done a lot of single player missions, skirmishes, etc and the shields I see from a distance with a probe are the same as I see close up. In single player I don't see any lag or shields changing abruptly. I am VERY glad to hear this is not exclusive to Universe At War. In UAW, I did lower the power on the TNG era ships (late/adv eras) and it seemed better, but I still hear the occasional complaint about bad readings.
I blame Internet lag for this, and the things that Bonk mentioned as well.
- Chris