Jenkins/Artifactory-plugin does not bypass http proxy

Given a default setup, the project requires Http proxy configured under: Jenkins->Manage Plugins->http proxy configuration.

Jenkins/Artifactory-plugin was installed with correct URI insert into field Artifactory server field. Checkbox marked with "Bypass proxy", saved, re-opened/re-started Jenkins ..

Performing a connection test to Artifactory fails with message:
"There is either an incompatible or no instance of Artifactory at the provided URL."

Artifactory's request log does not get any updates, thus looks like the Jenkins/Artifactory-plugin still tries to connect through the http proxy.

Plugin: v2.4.7
Artifactory Pro: v4.6.0
Jenkins: tested with v1.654 and v1.642.2

If we completely remove the proxy under Jenkins->Manage Plugins->http proxy, Artifactory can be connected successfully. Also connecting to an Internet Artifactory instance works, only the local instance on a different machine in network cannot be connected due to the missing proxy bypass.

Doing a test directly, via cURL, starting on the Jenkins master server:

 curl -Lvv http://xxx:8081/artifactory/api/system/version

delivers a success:

* About to connect() to xxx port 8081 (#0)
*   Trying 0.0.0.0... connected
* Connected to xxx (0.0.0.0) port 8081 (#0)
> GET /artifactory/api/system/version HTTP/1.1
> User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.15.3 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
> Host: xxx:8081
> Accept: */*
>
< HTTP/1.1 200 OK
< Server: Artifactory/4.6.0
< X-Artifactory-Id: abc:-8000
< Content-Type: application/vnd.org.jfrog.artifactory.system.Version+json
< Transfer-Encoding: chunked
< Date: Wed, 23 Mar 2016 15:44:34 GMT
<
{
  "version" : "4.6.0",
  "revision" : "40135",
  "addons" : [ "blackduck", "bower", "build", "cocoapods", "debian", "docker", "filestore", "filtered-resources", "gems", "git-lfs", "layouts", "ldap", "license", "npm", "nuget", "opkg", "p2", "plugins", "properties", "pypi", "replication", "rest", "search", "sso", "support", "vagrant", "vcs", "watch", "webstart", "yum" ],
  "license" : "abc"
* Connection #0 to host xxx left intact
* Closing connection #0
}

(some data were obfuscated)

Solution or workaround needed since this is a showstopper for usage.