This is an auto-filled bug because dev-db/mongodb fails tests. The issue was originally discovered on amd64, but it may be reproducible on other arches as well. If you think that a different summary clarifies the issue better, feel free to change it. Attached build log and emerge --info. NOTE: If you need further logs, feel free to ask..
Created attachment 638374 [details] build.log.bz2 build log and emerge --info
Fixed in latest ebuilds