R81.10 T30
A customer has defined a cluster interface in the topology of the firewall and installed the policy.
It turned out after that on one of the cluster members, that interface had a wrong IP so the VIP wouldn't show up under cphaprob -a if.
When it was corrected, the policy was pushed but the VIP still wouldn't show up until the trick described by @Timothy_Hall to disable accelerated installation was applied and then the VIP showed up.
Changing cluster properties seem to always cause a non-accelerated policy installation but, in this case, interface reconfiguration happened after so I suppose the feature bypasses topology update/refresh unlike non-accelerated installation.