When I click in a text field, the number 5 gets typed on its own and it keeps repeating until I press ESC. This also impacts Thunderbird, by auto tagging messages (hot key 5.) This problem is intermittent.
I've changed keyboard to rule out a hardware issue, but the problem still persists.
I am running Lubuntu 16.04, with the latest updates.
I recognize that this question was already raised. Unfortunately, I am new on here, so I could not comment, nor does the original question offer a suitable answer to this issue.
Could this be a bug?