I'm experiencing this on a K350 keyboard, on 4.4.0-21-generic kernel (fresh install of Linux Mint 18 Sarah / Ubuntu 16.04 LTS).
I usually see the problem after changing windows by clicking on one in the panel. As the new window takes focus, the 55555555...5555555's start flying.
Another curious symptom: occasionally, pressing the number "5" key while typing does not output anything. It just happened while I was typing this sentence.
But after having read all the above posts, I am going to try a kernel upgrade now. For some reason Mint has marked the kernel updates as "unsafe" which why I'm still on the release kernel of 4.4.0-21-generic.
I'm experiencing this on a K350 keyboard, on 4.4.0-21-generic kernel (fresh install of Linux Mint 18 Sarah / Ubuntu 16.04 LTS).
I usually see the problem after changing windows by clicking on one in the panel. As the new window takes focus, the 55555555. ..5555555' s start flying.
Another curious symptom: occasionally, pressing the number "5" key while typing does not output anything. It just happened while I was typing this sentence.
But after having read all the above posts, I am going to try a kernel upgrade now. For some reason Mint has marked the kernel updates as "unsafe" which why I'm still on the release kernel of 4.4.0-21-generic.
I will report my results.