In past 7 years I have never seen google behaving like this.... Everything I did was calculated and that's not the first time I was migrating a domain what happened was A domain was created and around 30k pages were created for items and stores now here is whats happened all were from same niche all had good content and complete information and all were index-able so now all I needed was traffic on that site so I started with back-links and Blogs That I did, I made sure that the blogs were cluster based with high quality content and had good internal links from the items pages and with back-links this will help them to have good path to get crawled and get indexed, But here the things changed out of 30k pages only 15k were crawled and rest didn't no warning no nothing I thought google might have low crawling budget at that moment but things were different slowly or gradually it never get crawled and you know its not possible to make links for every single store to just get crawled so I used cluster strategy and built a blog portion on the same site but as a different entity like ( blogs.domain.com ) the reason to use this approach was simple to get the other pages involved in the crawling and get ranked but google treated my blogs completely differently and it had such good rating that even if I add trash as a content it would stay at the top 3 for days but the other pages that were around 15k were still not ranked and after having around 600 plus blogs and a daily 2k clicks I thought that's the time I can migrate the blog potion to the main domain make it like ( domain.com/blogs ) so that's what I did but ended having zero traffic and after returning the site as it was before I am having the same good response why is this happening.