Yum repository soft repair doesn't work

Hello everyone.
I use Nexus OSS 3.16.2-01 and when my Yum hosted repository had grown to 1,5k+ packages I got trouble with soft metadata repairing. It doesn’t add new packages to metadata. Now I set up task with full metadata rebuild, but it takes too much time .
Any idea why soft repair doesn’t add new packages to metadata?

I think a bug report would be more appropriate here? https://issues.sonatype.org, the project is “Dev - Nexus”.