There’s a saying in software development that the smallest code changes are often the most expensive; a little change can have unintended consequences elsewhere. It appears that Apple may have provided another demonstration of this lesson with its first upgrade for the Apple Watch.

According to a story reported by Tech Times, Apple released version 1.0.1 of their Watch OS, which was designed to fix some security issues and improve Siri. According to the article, however, many Watch users started to post complaints on the Apple support forums and the MacRumors site. They said that instead of taking a pulse reading every 10 minutes as it had originally, some watches were taking an hour to take the next reading. The heart rate readings still work during workouts, and the Glance feature can be set to manually check the user’s pulse.

However, this is another stumbling block in Apple’s search for credibility with the broader medical and scientific communities. With their emphasis on the Research Kit’s value to medical research, a balky feature as simple as checking heart rate at regular intervals may lead researchers to question Apple’s commitment to the accuracy and reliability required to produce valid scientific results. It’s not as if Apple can’t afford to pay for thorough testing; some might choose to believe that the corporate culture favors form over function, and is more concerned about speed to market than getting it right the first time.