My site urbanindo.com recently experienced huge spike in traffic tracked by Google Analytics. The huge spike sometime shows in several same pages.

This is odd because I rarely experienced that much traffic before. Some pages can have hundreds of visitors at the same time.

But when I read the webserver log, those pages only showed up in only one or two entries, not hundreds like the GA showed. But the only similar thing about the entries is that they are using similar browser agent.

Mozilla/5.0 (iPad; CPU OS 5_1_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B206 Safari/7534.48.3
Mozilla/5.0 (iPhone; CPU iPhone OS 5_1_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B206 Safari/7534.48.3

And when I opened the Google Analytics > Audience > Technology > Browsers & OS and I plotted the chart based on the browsers, I saw that the huge spike came from Safari.

This huge spikes started to happen since the beginning of this August, which happens to be when I use multiple webservers behind load balancer (although I'm pretty sure those two are not relevant).

Is there something wrong with my GA configuration?