Konsole screen corruption

Konsole screen is corrupted .. i.e. not showing true contents of a file. Observed in nano and the THE editors and possibly in vi.

Given the file:

test of screen problems in Bionic beta 2
03/09/18 xxxxxxxxx yyyyyyyyy zzzzzzzzz qqqqqqq
03/23/18 qqqqqqqqq rrrrrrrrr sssssssss ttttttt
03/29/18 aaaaaaaaa bbbbbbbbb ccccccccc ddddddd
04/06/18
04/13/18 ddddddddd eeeeeeeee fffffff

the first screen shown in nano or THE will be:

test of screen problems in Bionic beta 2
03/09/18 x y z q
03/23/18 q r s t
03/29/18 a b c d
04/06/18
04/13/18 d e f

This occurs in Konsole under Kubuntu 18.04 beta 2 in xfce4 as well as Plasma.

Description: Ubuntu Bionic Beaver (development branch)
Release: 18.04

konsole:
  Installed: 4:17.12.3-0ubuntu1
  Candidate: 4:17.12.3-0ubuntu1
  Version table:
 *** 4:17.12.3-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status

NOTE: The above problem does not occur when using a REAL console session.