I have installed newest plg_jsocial_share_4.1.0.zip and Firefox 45.0.1 browser.
On non-secure (http://) pages plugin works ok.
But butons "Google+" and "VK ShareB" are not rendered on secure (https://) sites – problem is that modern browsers are blocking part, that are not secure. On Firefox developer toolbar you can see these problems with security:
Blocked loading mixed active content "http://vk.com/js/api/share.js?91"
Blocked loading mixed active content "http://apis.google.com/js/plusone.js"
Solution is pretty easy, only replace "http://" with "https://" in file "/plugins/jshoppingproducts/jsocial_share/jsocial_share.php", especially on rows 76 and 105 in version 4.1.0.
Plugin will be working on both secure and non-secure pages.
May be this solution solve most problems with lost buttons for Social Share plugin on this forum.