Hi @Bradley Kean ,
I couldn't reproduce this issue on my end. I can get the pages in the subsite form the search results no matter if the filter is set to All sites or subsite only. To narrow down this issue, please check the following:
- Go to Site Settings of your subsite > Search > Search and offiline availability > Make sure "Allow this site to appear in search results?" has been set to "Yes".
- Make sure search filter has been set to subsite/Files/All file types when searching.
- Are all pages in the subsite cannot be shown in the search results if set the filter to the subsite?
- Go to Site Settings of your subsite > Search > Search and offiline availability > Reindex site, then go to search service application in the Central Administration and start a full crawl. Search again in the subsite after the full crawl is completed.
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