I read in the comments that the Dislikes was getting removed. I found out that the first time you dislike the video, it doesnt work but right after refreshing the page and disliking again, it works. I don't think there's any lag, this is YouTUBE that we are talking about. Their servers and frameworks should be top of the line.

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https://www.youtube.com/watch?v=fKZhNMGAsCQ

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