I don't use Midnight Commander (
bmon at all, but I took a look at them.
Basically with Putty, I have Window > Translation > Character set received set to
UTF-8. Then during my Putty session, envvars are set to
mc looks correct with line characters. It even works with the mouse, wow! However,
bmon has the "lqqqqqk" display problem.
I then installed
ncurses-term for the
TERM=vt-utf8, and then ran
env TERM=vt-utf8 bmon, and the display looks a bit better with line art. There is some small problem with the close dialog box, though.
I suggest shell aliasing or wrapping your
env TERM=vt-utf8 bmon and leaving your LANG set to humanlang.UTF-8 alone.