When you have 1 VA defined per host in a cluster for VA hotadd-based replication, you need to exclude the VA(s) from moving around as part of DRS VM load balancing.
The answer to the question of 1 VA per host or 1 VA per cluster has not been clearly answered, but a 1 VA per clustercapability is being looked at for inclusion into a future vRanger 5.x.x release.
Exclude the VA from participating in DRS. This is described in detail in the VSphere Resource Management guide linked below.
1. Select the cluster in vSphere management client.
2. Click on the DRS tab and click Edit.
3. Click Virtual Machine options - ensure the "Enable individual virtual machine automation levels" is checked
4. Select your VA from the list and under automation level, select "Manual"
This will ensure the VA is not participating in Distributed Resource Management.