Load monitor Plasma widgets get stuck

[solitone <solitone@mail.com>]

Hi,

I notice that after some time of regular behaviour, load monitor widgets 
like CPU Load Monitor, Memory Status, and Hard Disk I/O Monitor often 
get stuck and don't update information displayed any more.

I'm on stretch:

~$ apt-cache policy plasma-desktop
plasma-desktop:
  Installed: 4:5.8.6-1
  Candidate: 4:5.8.6-1
  Version table:
 *** 4:5.8.6-1 500
        500 http://ftp.it.debian.org/debian stretch/main amd64 Packages
        100 /var/lib/dpkg/status

~$ apt-cache policy plasma-widgets-addons
plasma-widgets-addons:
  Installed: 4:5.8.5-2
  Candidate: 4:5.8.5-2
  Version table:
 *** 4:5.8.5-2 500
        500 http://ftp.it.debian.org/debian stretch/main amd64 Packages
        100 /var/lib/dpkg/status

Anyone experiencing the same thing?