Sometimes I also experienced the same error, at that time I will re-run the solution then this error will vanish.
So I didnt much care about this issue.
Today you reminded me this issue, which catch my eye to see what and why this error occurs?
I would like to share this link
] which help me to understand the actual behind the screen of the problem.
I know some might not care about how the error is,will ya?
For solution refer this link