The storage UI will show "NAN undefined" for max storage size if you use one of the sharding-cluster storage templates (any of these), https://www.jfrog.com/confluence/display/RTF/Configuring+the+Filestore#ConfiguringtheFilestore-ConfiguringShardingforHACluster, as long as <provider id="sharding-cluster" type="sharding-cluster"> is part of the chain. We use cluster-s3, but it seems to affect all of them.
This "NAN undefined" text will go away if you stop artifactory on all but one node in the sharding cluster and then it will show the correct max storage size. The cache-fs storage tracker is unaffected and works properly regardless.
I have reproduced this across each of our artifactory clusters, so it is not unique to one environment. A similar issue was reported here: RTFACT-14068