A growing flood of mobile coffee orders is causing bottlenecks and scaring customers away from some busy Starbucks locations. Mobile payments have been championed as a way to boost business and efficiency while keeping labor costs down, but baristas are having trouble keeping up with the pace. In a conference call yesterday, Starbucks chief Howard Schultz said the company is "hyper-focused" on fixing the problem. The Seattle coffee giant posted disappointing earnings yesterday and lowered its revenue forecast for the year. Read more from Reuters here.