vbucketctl list returns wrong magic sometimes

using build 1.6.0a-54...

Every once in awhile, I see this "Got magic: 97" error output from vbucketctl list. This only started happening after # of vbuckets was increased to 256.

For example...

$ ./management/vbucketctl.py 10.1.3.106:11210 list
Traceback (most recent call last):
File "./management/vbucketctl.py", line 18, in <module>
c.execute()
File "/Users/steveyen/work/northscale/dev/ep-engine/management/clitool.py", line 33, in execute
f[0](mc, *sys.argv[3:])
File "./management/vbucketctl.py", line 6, in listvb
vbs = mc.stats('vbucket')
File "mc_bin_client.py", line 227, in stats
cmd, opaque, cas, klen, extralen, data = self._handleKeyedResponse(None)
File "mc_bin_client.py", line 69, in _handleKeyedResponse
assert (magic in (RES_MAGIC_BYTE, REQ_MAGIC_BYTE)), "Got magic: %d" % magic
AssertionError: Got magic: 97