You are correct, there was an update this past August, and within the release notes is this comment: 

"Fixed – StableLoc issue when transitioning to the next best correction source, resulting in a position shift"

I do not know if this description is referring to the issues I encountered or the issues the OP encountered.  In many of my issues, I never lost the correction source, whether it was TS or RTK, but the line would still jump.  I have not tried running with StableLoc enabled for quite a while.