seo for youtube videos change??

i use gsa ser and dump thousands of black links to my videos. anchor text being just keyword i want to rank for. this use to work great.... i got videos on the first page of youtube in a week or so using this method....recently i have noticed a lot of these videos have been 'de ranked' and i'm not raking like i should....what's changed? is building back links to youtube videos a slow process now?thanks

SEO is catching up to everything, SPAM is never a good option to be implemented on quality.

Didn't experiment it. I also blast my YT videos to get rank and I didn't see any slap in rankings

You need to do it slowly and drip feed,its still working for me.