Note: the symptoms are very much like (maybe even exactly the same as) those
of bsc#904214 reported some time ago on 13.2. I also tried the trick from
bug 904214 comment 8 and it works.

On current Tumbleweed, most control keys, including backspace or tab, are
processed incorrectly on text console (VT), resulting in inserting a character
which cannot be displayed; echoing it through 'od -t x1' shows 'ef 80 80'
which should be U+FOOO in UTF-8. Few keys work correctly (e.g. arrows or
"Delete") but most seem to be mapped to this character, making work on VTs
unbearable.

The issue doesn't seem to depend on localization, I'm not using any national
keyboard map (selected "English (US)" on install) and the issue affects both
root (LANG=POSIX, LC_CTYPE=cs_CZ.UTF-8) and regular user (LANG=cs_CZ.UTF-8,
no LC_* set).

First time I noticed this was around half December but it's possible it has
been broken earlier. The issue persists after updating everything to latest
updates this morning (2017-01-11).