VMware has just posted an article in the Virtual Blocks blog which describes this behaviour. It happens only when trying to Storage vMotion a virtual machine with a swap file larger than 64GB to the vSAN datastore.
The task fails and generates the following error messages:
There are two possible workarounds available: either increase the swap file maximum size on the destination ESXi host or set a reservation of memory on the virtual machine. The former one is more preferable, as it does not require host reboot.
VMware provides a KB 2150316 with “more log samples and specifics for identifying the issue as a cause of a migration failure”.