SUMMARY If a konsole window/tab has been open for a long time, at some point it simply stops accepting any keyboard input (including tab-switching with Shift-Left/Right). Always reproducible with windows/tabs that have been restored during session start-up. STEPS TO REPRODUCE 1. Leave a konsole window/tab open as part of your saved&restored session 2. Start KDE 3. Don't type anything into said konsole window 4. Leave the session running for at least a few hours OBSERVED RESULT Keyboard input typed into the konsole window has no effect whatsoever. EXPECTED RESULT konsole should work as usual.
This was actually an ibus related issue. Opened a new bug with appropriate title & steps to reproduce as #420464 *** This bug has been marked as a duplicate of bug 420464 ***