The Case of the Missing Characters

In the last 2-3 weeks, I have had the following happen on at least 2 occasions. Someone also mentioned it on fedoraforum.org, so this is not unique to my keyboard.

I have noticed that when I am typing, the letters v,b,f,g,r,t,4,5 do not always type, making it very difficult to write emails and enter commands. The curious thing, as I just ascertained a moment ago, is that the missing characters all line up diagonally on the keyboard.

I am using the pc105 character german keyboard setting with all dead keys, like it is supposed to be, and have the system set to use utf-8, which is the default. I have also enabled the xkbd compose key option, although I don't really need it, having an international keyboard with dead keys, on the useless key to the left of the right ctrl key.

Could there be some problem with keysim mappings or something? I thought that, since the keys all line up, that there could be a problem with the keyboard, but as I had said, it has only happened twice in the last 3 weeks and someone else reported the problem on fedoraforum about 2 weeks ago.