SwiftKey's typing predictions may have leaked users' emails

The company has suspended a syncing feature as it fixes the problem

SwiftKey, a popular keyboard app, has suspended a syncing feature that may have leaked users’ emails to strangers.
The problem has been popping up through the app’s prediction bar. A few users on Reddit have noticed that it’s been offering strange suggestions -- including emails they’ve never seen and foreign language terms they’ve never used.

“And now, I'm getting someone else's German predictions,” wrote one user, who recently rooted a Samsung Galaxy S6 phone. “I have never typed German in my entire life.”
The problem might be related to how SwiftKey collects data on the words and phrases users type. That data is then analyzed and used to predict the customer’s typing habits, including what emails they tend to enter -- only in this case those predictions are possibly being shared to others.  
“I just went to the Gmail login ID field and I saw someone else's email as a suggestion,”wrote another Reddit user, who noticed the problem after factory resetting a Samsung Galaxy Note 4 phone.
The problem hasn't affected most users, SwiftKey said in a blog post on Friday. But to fix the problem, it has been removing email predictions from the app. 
The company has also turned off the app’s cloud sync service. This allowed users to share their typing habits across SwiftKey apps installed on different devices.
Microsoft, which bought the app earlier this year, hasn’t said when the cloud syncing feature might return.