I run regularly scan of some selected sites using SSL Labs API. On the 5th of December, I've noticed that one of the sites has received the grade F by automated scan. When I ran the scan manually via SSL Labs Server Scan site, the grade was A, like it was before. Subsequent scan using SSL Labs API returned A too. When I compared json responses from both scans - when grade was A and when grade was F - there was no difference except in timestamps of scan execution.
Is it expected that such behavior can occur when scanning using SSL Labs API?
Thank you for any feedback.