Ok, I understand now what is the issue. Before the HD channels were not working since quite some time. Now the HD channels are the only one working. Any try to go on SD channels make Kaffeine segfault. But you can go from any HD channel to any other without problem. Before only the first HD channel selected in the evening was viable, all others produced artifacts. So it is a change done that allows HD, but breaking SD, this is what one has to search for. Unfortunately I cannot revert back any more (as apparently I did not set sufficiently high the number of snapshosts.