I was just talking to someone about the Apple Watch, and how the person was most attracted to the gadget because of its heart rate sensor. Sure, there are other fitness bands equipped with that tech, but the Apple Watch does a nice job of mixing fitness data with smartwatch functions. And, according to one report, it does so really well. The latest update is apparently causing issues for some users, however.

MacRumors noticed folks on the Apple forums and on its own forums who have noticed that the Apple Watch isn’t sending heart rate data to the Health app as consistently as it used to.

“I also noticed that my heart rate data in the health app for about a week period is gone and my heart rate data is now updating into the app intermittently,” one user said, according to MacRumors. Apple Support suggested cleaning the sensor, but that apparently didn’t solve the problem, which appears to be software related.

The good news is that this doesn’t seem to be affecting everyone. Talk about a frustrating bug for folks who are relying on the Apple Watch while working out or, more importantly, to actually share that data with health professionals. Hopefully a fix is in the works and hits sooner rather than later.