After updating drupal core from 8.5.3 to 8.5.6 and then to 8.6.2, the upload function for inline images does not work anymore
In my case it still works on content type "basic page", but it does not on "articles".
Same issue including screenshots is described here:
https://www.drupal.org/forum/support/post-installation/2018-08-24/ckedit...
As you can see on the following screenshot, after chosing the file, only the file name is taken to the upload bar, but not the file itself. You cannot click the filename to open it. https://i.stack.imgur.com/dp7In.png