bug#32282: octave-mode not unmarking region

[juangdse]

from within emacs open the following script file

--------
# octave script script.m

x = pi ;
--------

Then do

1. set editing to octave-mode (M-x octave-mode).
2. mark the entire line "x = pi ;" as a region
3. issue the command `octave-send-region' (C-c C-i r).

expected result: command is executed and region is inactive
actual result: command is executed but region is still active

This happens now consistently with the current live Ubuntu 18.04 LTS after 
installing emacs25 and octave-4.2.2. -- However, I see the behavior on and off 
for at least 3 years.