I have noticed a few times today an unusual behavior of the built-in virtual keyboard on my Nexus S with Jelly Bean 4.1.1. When I type text in different apps (e.g. Google+ Messenger, Google Drive), the keyboard suddenly and unexpectedly disappears, and text editing mode is terminated.
This premature interruption is triggered at apparently random moments after typing a different amount of text each time (from a couple to a few tens of characters), but approximately after the same amount in the same session. Rebooting the phone fixed the issue the first time, but had no effect in subsequent instances.
Some context and details. I use the device in Italy and the system language is Italian. I switch between using two languages with the keyboard, Italian and English. The premature interruptions seem to happen mostly when using the keyboard with Italian, and when typing fast. This issue never happened before today.
What causes this problem? How can I fix it?