4.5.1 centos/suse only - bucket flush failure

There are two tests failing BucketFlush and DMLQueryTests. But both are failing with error flushing the bucket.
This is happening only for 4.5.1 and on Centos and SuSE. (Not on debian and ubuntu).

You can see the build history here: http://server.jenkins.couchbase.com/view/build-sanity/job/build_sanity_matrix/ (also a test job here, where I was running it on different builds to see when it started occurring: (http://server.jenkins.couchbase.com/view/build-sanity/job/build-sanity-1node/)
Search for 4.5.1 builds and you can see the issue. I want to say the issue happens starting from 4.5.1-2749. But I am not certain of that. Until this morning it failed on 2749 for both BucketFlush and DMLQueryTests. But I triggered the sanity run on 2749 again an hour back and now it failed only for DMLQueryTests (with the same unable to flush bucket error), but BucketFlush test did not fail.

Assigning to Ritam to triage.