Update: This issue has been fixed. Realtime data and smart insights should be back now. View counts for the affected videos have been restored. Thanks for your reports!https://twitter.com/TeamYouTube/status/1159885087636246534 …
There are several factors that contribute to likes/dislikes count changes. Some may be marked invalid and periodically removed from the counts. Other factors are found here: https://yt.be/help/WS2j . Hope this helps clarify!