Artifactory virtual repo: Some files can't be downloaded (Zero bytes sent to client but expected XYZ bytes)

I am using Artifactory Pro version: 3.6.0. I have couple of remote repos (caches) configured proxying out to different exteal repos (like https://repo1.maven.org/maven2/...) I also have a virtual repo configured which includes all the remote repos. (for example: http://mydomain/artifactory/remote-repos/...)

After Artifactory server restart I realized that some maven builds started failing because some of the maven plugin related pom files (dependencies) can't be downloaded/fetched from Artifactory.

I noticed that the file can't be downloaded trough the virtual repo URL but can be downloaded trough the remote repo URL.

For example:

(Just some 1-2 maven plugin related pom files can't be downloaded; The rest of the files downloaded okay.)

I need to use the virtual repo URL because that is how it is configured in settings.xml file (mirrored central cache)

I did a lot of different investigation:

1. Cleared the Artifactory proxy cache and all build server maven caches; These forced to re-cache the files

2. Looked at Artifactory logs (both info and debug levels)

   ...

   [DEBUG] (o.s.j.d.DataSourceUtils:110) - Fetching JDBC Coection from DataSource

   [DEBUG] (o.a.s.d.u.JdbcHelper:98) - Query retued in 521032 nanos : 'SELECT * FROM nodes WHERE repo = 'remote-repos' AND node_path = 'org/apache/maven/maven-parent/26' AND node_name = 'maven-parent-26.pom''

   [DEBUG] (o.s.j.d.DataSourceUtils:327) - Retuing JDBC Coection to DataSource

   [DEBUG] (o.a.r.RepoRequestContext:71) - 8b83e9a2 get admin remote-repos:org/apache/maven/maven-parent/26/maven-parent-26.pom Identified requested resource as a file

   [DEBUG] (o.a.r.RepoRequestContext:71) - 8b83e9a2 get admin remote-repos:org/apache/maven/maven-parent/26/maven-parent-26.pom Requested resource is an ordinary artifact - using normal content handle with length '40751'

   [DEBUG] (o.s.b.f.s.DefaultListableBeanFactory:523) - Retuing cached instance of singleton bean 'pluginsAddonDefaultImpl'

   [DEBUG] (o.s.b.f.s.DefaultListableBeanFactory:523) - Retuing cached instance of singleton bean 'org.artifactory.addon.plugin.PluginsAddonImpl#0'

   [DEBUG] (o.a.r.RepoRequestContext:71) - 8b83e9a2 get admin remote-repos:org/apache/maven/maven-parent/26/maven-parent-26.pom Executing any BeforeDownload user plugins that may exist

   [DEBUG] (o.a.r.RepoRequestContext:71) - 8b83e9a2 get admin remote-repos:org/apache/maven/maven-parent/26/maven-parent-26.pom Responding with selected content handle

   [DEBUG] (o.a.r.RequestResponseHelper:71) - Sending back body response for 'remote-repos:org/apache/maven/maven-parent/26/maven-parent-26.pom'. Original resource size: 40751, actual size: 40751.

   [WARN ] (o.a.r.ArtifactoryResponseBase:57) - Zero bytes sent to client but expected 40751 bytes.

   [DEBUG] (o.a.r.RepoRequestContext:71) - 8b83e9a2 get admin remote-repos:org/apache/maven/maven-parent/26/maven-parent-26.pom Request succeeded

   ...

3. Checked if file exists on Artifactory: Exists and can be downloaded using remote repo URL (not virtual repo URL); See above.

4. Tried to restart Artifactory couple of more times (restarted with no issue)
5. Created a new Artifactory virtual repo and started to use the new URL but same things happened than with the old one

Anybody has any idea why some of the files (like maven-parent-26.pom) can't be downloaded from Artifactory using the virtual repo URL?

Thanks.