Search issues in 11.x

Hi iam seeing search issues on my environment i seen same on Telligent site also, iam in wiki of 11.x and search with a key word it shows Wikis 33 

if we go for advanced search from there it shows wikis 149 .

this happens in our environments also vs 11.1.8.17149  .

It is  giving wrong results to the end user. Can you please explain me what's happening over here and how we can correct this.