is:open shows merged pull-requests in search

It seems that in GitHub search I get some merged pull requests when I set the filter: is:open

This is a query example that includes those merged pull-requests: org:canonical-web-and-design is:pr is:open archived:false author:tbille author:jkfran author:jpmartinspt author:nottrobin author:carkod

Or the link: https://github.com/search?q=org%3Acanonical-web-and-design+is%3Apr+is%3Aopen+archived%3Afalse+author%3Atbille+author%3Ajkfran+author%3Ajpmartinspt+author%3Anottrobin+author%3Acarkod

Is this a bug or am I missing an argument here?

Thanks,

toto

Hi @tbille,

Thank you for being here! Occasionally our search index information can fall behind, so I’ve triggered a reindex of the Pull Requests Index for the canonical-web-and-design org.

Please refresh your search query and let me know if there is an error in the search results (including merged pull request).