Unwanted code, like below, is displayed on articles when System -> Global settings -> Cache is set to ON (both for conservative and progressive caching). The first time the article is loaded it looks ok but when reloading it garbage code like below is displayed. System is Joomla 3.4.8.
Example of unwanted code displayed:
This is generally caused by a third party plugin. To track down which one is causing this you need to disable plugins one by one and clear the cache before reloading (reload at least twice).
In my case, it was a plugin called Content – Facebook-Twitter-Google+1 causing the trouble. I tried reordering the plugin, from first to last without any success so I simply just had to ditch it and find another one.
I found out that the BT Social Sharing plugin was a better alternative. Apart from not giving the above trouble it doesn’t slow down the site as the Facebook-Twitter-Google+1 plugin did.