The long-rumored “iWatch” from Apple failed to make its debut last year, despite reports early in the year that Apple was working hard to get it out by the end of 2013. Samsung, on the other hand, managed to release its Galaxy Gear smart watch, which turned out to be a mild success despite its lack of features.

Now a new report could shed light on why so few smart wearable devices launched in time for the 2013 holiday quarter.

According to a DigiTimes report, manufacturers are currently struggling with yield rates as low as 50% for their wearable devices. More specifically, the report’s unnamed “sources from the upstream supply chain” say that manufacturers are reportedly having trouble with surface treatments applied to metal injection molded components.

The brands affected by these yield issues reportedly include Apple and Qualcomm, which released its Toq smart watch one month ago. DigiTimes’ sources believe that quality concerns combined with the large supply needed for product launches has resulted in the yield issues causing delays.

Though these issues seem to have delayed a number of product launches, consumers can still expect a wide variety of smart watches and other wearable devices to launch this year. Both tech device manufacturers and apparel companies (such as Nike and Adidas) are diving into what they see as the next big device segment.