Hi all
Updates on this case. After migrating hdds to other datastores that are not over allocated, the vms are working in a stable mode. No more error on vmdk files.
So I'm pretty sure it's a bug that vsphere host or vcenter does not think datastore has free space for vmdk file on over allocated datastore even when there is actual free space in the datastore. vm hosts are thin provisioned in this case.
Hopefully vmware can address this bug and release a fix.
Cheers