I've got one physical host in a 3 host CentOS7.5 cluster that reports the following error several times a day

VDSM node3.example.com command Get Host Statistics failed: Internal JSON-RPC error: {'reason': '<Fault 1: "<type \'exceptions.AttributeError\'>:\'NoneType\' object has no attribute \'statistics\'">'}

Any ideas what the problem might be?