Actual content. Like publishing 10 articles, 8 are OK, 2 are crawled, but not indexed and Google refusing to do it no matter what. Not even money articles, just informative piece of content or news. Its pretty weird and is happening across multiple sites...I've seen some wonky indexing issues over the last year or so but for the last couple of weeks, I thought they've been doing pretty well. I've got new and aged domains indexing content pretty quickly.
Is it spammy backlinks or actual content you're trying to index?