Hi,
Here is what I can tell you as I have the same issue with a VNX 5300, and I am completely disgusted with VMware's attitude of dealing with it.
The issue is stale entries in the hostd cache. Rebooting the hosts or restarting the management agents do not fix the issue. I have been assured by VMware that no data is at risk it is purely a reporting function.
The only current fix is a storage vmotion of the affected VM's.
I chased VMware after they closed my support case with a status of resolved after having done very little!
They said they have a number of calls about the issue and it is a known bug being dealt with by their engineering team. I then discovered they have known about the issue since February 2014. I then challenged as to why there was no KB article and they have now begun writing an internal KB which will be published in a few days...
I will update when I have more...