Right, it requires changing $LANG to something else in order to reproduce, will apply.

Futher remark: Maybe the "display" variable in question depends on termcap related configuration which might be different on our systems.

Hm... are you sure about reproducer?

$ ./screen -d sleep 9999
There is no screen to be detached.

Tried also with -dm, but it seems to work?
$ ./screen -dm sleep 9999
$ ./screen -Q info
(1,1)/(80,24)+5000 +(+)flow bce UTF-8 0(sleep)%
$ ./screen -ls
Your inventory:
        5071..hostname (Detached)
1 Socket in /home/amade/.screen.

Can you check with current release 4.6.0?

repro:
$ screen -d sleep 9999
$ screen -Q info
$ screen -ls
There are screens on:
        28239.pts-101.XXX-queryA        (05/04/17 09:24:25)     (Dead ???)
        28239.pts-101.XXX       (05/04/17 09:24:25)     (Dead ???)
Remove dead screens with 'screen -wipe'.

Unfortunately in Debian there are only very old debug symbol files of version 4.2.1 (but I can also repro on 4.5.0), so gdb trace is from the old version:

(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x0807a564 in ShowInfo () at process.c:5647
5647    process.c: No such file or directory.
(gdb) bt
#0  0x0807a564 in ShowInfo () at process.c:5647
#1  DoAction (act=0xfff8600b, key=-1) at process.c:1857
#2  0x08080b61 in DoCommand (argv=0xfff8707c, argl=0xfff8717c) at process.c:4567
#3  0x0805ff59 in DoCommandMsg (mp=0x80bb000 <m>) at socket.c:1807
#4  0x080620f1 in ReceiveMsg () at socket.c:1220
#5  0x08090630 in sched () at sched.c:237
#6  0x0804c463 in main (ac=<optimized out>, av=<optimized out>) at screen.c:1487
(gdb) show directories
Source directories searched: $cdir:$cwd
(gdb) dir /tmp/screen-4.2.1
Source directories searched: /tmp/screen-4.2.1:$cdir:$cwd
(gdb) l
warning: Source file is more recent than executable.
5642        }
5643    #  ifdef UTF8
5644      if (wp->w_encoding != UTF8)
5645    #  endif
5646    # endif
5647        if (D_CC0 || (D_CS0 && *D_CS0))
5648          {
5649            if (wp->w_gr == 2)
5650              {
5651                sprintf(p, " G%c", wp->w_Charset + '0');
(gdb) info registers
eax            0x0      0
ecx            0x7      7
edx            0x80cb2d8        135049944
ebx            0xfff8600b       -499701
esp            0xfff85f70       0xfff85f70
ebp            0x0      0x0
esi            0x1      1
edi            0x0      0
eip            0x807a564        0x807a564 <DoAction+20740>
eflags         0x10246  [ PF ZF IF RF ]
cs             0x23     35
ss             0x2b     43
ds             0x2b     43
es             0x2b     43
fs             0x0      0
gs             0x63     99

Clearly there is an invalid dereference most likely due to uninitialized variables when screen is started in detached state.