Hi Ernest, and thanks for your insights !
Yeah, i kinda figured out when debugging the issue, that wordpress loads his own Jquery (except in child themes, where you have to add some code apparently), and reading here and there that you should use this version when developping plugins for wordpress. For simplicity, scope issues, loading times, … and mostly because it's already bundled in WordPress. And modifying wordpress when using one plugin is not something you can tell your clients.
So yeah, i did change a lot of things, including moving the calls in the functions.php (enqueuing), uing jQuery(something) instead of $(something) etc etc.
I dont see any performance change, but the problems have disappeared. And… i even fixed an issue with a call i made in photon where i was trying to reset the facebook call for sharing an article, and got errors in the console even if the share worked fine. So i guess i even fixed that too.
I had issues with linkedin, though, and had to replace the share button. But meh, i'm fine with it.
I only have ONE issue now, which is not causing me any trouble i guess, but prints an error in the console. After a couple clics i got this 'KeyboardEvent.keyIdentifier' is deprecated and will be removed in M53…
but i THINK it's because i use Vivaldi and got an update yesterday. Just wanted to let you know, cause maybe some calls to your functions use this, and might get obsolete with the next chrome version (vivaldi uses chromium).
Thanks again for the long answer and your enlightments, they really helped !