For me, CTR is ok during the earlier part of the day. Australian traffic, UK to a certain extent, and US traffic in the morning all look normal. But after late noon until the end of the day, the clicks just slow down a lot, and often completely stop.
It's like a moratorium has been placed on my account. This has not been the case for as long as I've used Adsense. In the past, the clicks always come through during the whole day. There is no "drying up" phenomenon.
So much so, that even though I might have a good start to the day, but I kind of know how it turns out later, and I've learned not get my hopes up. The pattern has changed, showing a marked turn from late April. The question is, is this natural or due to Google interfering?