Hey there,
That sounds pretty strange for sure! You are able to toggle off specific toolkit items on each post within the post editor. That would be one of the next places to check!
I also noticed that you are running SG optimizer and it could be optimizing Grow! We do have some instructions for excluding Grow from popular optimization plugins.
SG Optimizer is the third option down the page. Here is a link to that help doc!
Thank you, this worked for me and the social sharing buttons are now visible again.
kind regards, Bec