Nexus OSS 3.26.1-02 does not find maven artifacts anymore / likely corrupt metadata

After upgrading to OSS 3.26.1-02 our builds frequently fail because nexus does not deliver the deployed maven artifacts anymore.
After running the Task “Repair - Rebuild Maven repository metadata (maven-metadata.xml)” nexus works correctly again.

1.) Build and deploy maven artifacts to nexus, e.g.

2.) Try to build an artifact depending on (1), e.g.
cd dao-impl; mvn --update-snapshots clean deploy

Expected: Success
Actual: Failing due to the following error:
ERROR] Failed to execute goal on project dao-impl: Could not resolve dependencies for project …: The following artifacts could not be resolved: …:dao-api:jar:5.1.0-SNAPSHOT: Could not find artifact …:dao-api:jar:5.1.0-SNAPSHOT in nexus (http://nexus/repository/maven-all/) ->

3.) Execute Task “Repair - Rebuild Maven repository metadata (maven-metadata.xml)” on nexus

4.) Repeat (2) --> now the mvn build is successful as nexus delivers …:dao-api:jar:5.1.0-SNAPSHOT

Nexus logs are telling basically nothing.
No errors.
Only 1 warning (repeated a couple of times):
2020-08-18 09:04:48,012+0000 WARN [quartz-9-thread-12] *SYSTEM com.sonatype.insight.scan.client.ClientScanner - Could not locate client info descriptor

As a downgrade is not possible: Any hints how to fix this issue?

Looks like you’re hitting this bug:

There is a patch available on that issue which fixes it. To specifically fix any 404 responses from GAV level maven-metadata.xml files download the GA level file, that will force the files below it to rebuild. E.g.