I've just grabbed the home page of the forum without being connected to it (with the 'clip simplified page' option), and then, in joplin desktop I noticed the page grabbed twice or more time (even 4times when I try to reproduce). I was waiting in front of the webclipper popup to get the page without doing anything else, quietly 
this concerned joplin desktop v 1.0.143
edit: this seems to be tied to discourse as the grabed home page is not the same in term of image content (the resource ID changed but I dont know why), but that does not occurs when we are connected