RHV 4.3.9 contains a bug which highly impacts TrilioVault up to the point of being unfunctional.
A Red Hat Hotfix is available from TrilioVault Customer Success.
The patch will be included officially in RHV 4.3.10
ovirt-imageio 1.5.2 and 1.5.3 contain a change compared to 1.5.1 which breaks TrilioVault.
Please contact TrilioVault Customer Success for the necessary changes.