The company is "investigating a fix for a future software release", Apple spokeswoman Amy Bessette told Reuters.
The watch doesn't require a new data plan, but an add-on to existing plans.
Aside from a slight bump in its processor, the new Apple Watch is really riding on a single feature to make it appealing to those considering an upgrade, and that feature is LTE.
A number of reviewers this week have complained that their cellular-enabled, third-generation Apple Watches were having connectivity issues, wreaking havoc on some the watches' most significant new features. Unlike previous versions of the watch, it has cellular network connectivity built in. In a review, The Verge found that cellular service was unreliable, and handoff wasn't working as it should.
The mixed reviews weighed on Apple shares, which were down about 2 percent at $155 in afternoon trading.
Tips for Canadians caught in Equifax's security hack
Analysts say three Equifax executives, though, may have a hard time explaining their series unusual stock sales. An investigation into the data breach was launched last week by Canada's privacy watchdog.
Apple replaced Lauren Goode's review unit, but she had problems with the second Apple Watch too.
The tech giant unveiled the Series 3 last week, alongside the iPhone X, iPhone 8 and iPhone 8 Plus.
After tests of a Watch Series 3 device revealed the flaw, the Verge got in touch with Apple.
It is not clear how often the problem occurs or how hard it will be for Apple to get the release to Watch buyers.
For business users, iOS 11's Mail application had problems sending mail for Microsoft Exchange and Outlook.com mail accounts.