False Alarm!
This seems to occur since the volume got mounted by v4.1(https://bugzilla.redhat.com/show_bug.cgi?id=1375259) and I missed that while opening this BZ.
Mounting via v4.0,the perf regression for this test is within limits that my tests are allowed to have between releases/dev builds.
Closing as Nab,and appologies for the unnecesssary noise.