Indexed though blocked by robots.txt file error will be seen in new search console even though they are blocked by robots.txt file the urls listed in this section will be interesting for every seo.
In Google New search console indexed though blocked by robots.txt file means the urls of that directory is blocked by robots.txt preventing from crawling but not telling Google Bot or spiders from preventing index in Google so that will be indexed. That is why few urls which are blocked by robots.txt file will be listed there and it may be huge in number. In order to have them take out those pages from Google search you have to make sure that Google Bot can crawl those pages and see a no-index tag on those pages to prevent indexing from Google.
If you see list of your WebPages under indexed though blocked by robots.txt file its better to understand what exactly Crawling and Indexing means and how Google spiders and Google consider them.
Difference Between crawling and Indexing:
Crawling and indexing are both separate. Crawling is the process of spiders to find new and updated articles of your website and get them indexed and organize information available to other visibly in Google search index and robots.txt is only for crawling.
Indexing is the process of spiders doing the rest of job to get them indexed in search index after crawling process is done. After a page is discovered by Google bot spiders then Google tries to understand those pages and as per their search algorithms Google indexes them as the page is relevant to.
After reading once you know the difference between indexing and crawling then you will understand why url are listed in search console saying indexed though blocked by robots.txt file.
More Google SEO Article:
What to Do if Indexed Though Blocked by robots.txt file:
Just leave them that’s not going to hurt your website in ay means. In this case what new search console is reporting is what’s happening with your website and giving you information to improve your website. They are blocked by robots.txt file and Google Bot respects robots.txt and doesn’t crawl those pages but will be indexed in a scenario when those urls could be linked to from other pages on your site in this situation Google will index if they are linked from external url source also. As Google bot follows from link to link page when a page crawls.