Synthetic full skipped when adding a virtual into a VM group

Hi,

Here is my situation :

For a specific server plan, a synthetic full is missing for July and August. We have extended retention for this server plan on AirGap so that one full by month is kept for a year. I have Synthetic full with all VMs of the subclient for : May, June and September but I don't have Synthetic full for : July and August. The difference between these months is that we added a virtual machine in July and August. At the time of addition, there are full backups to back up only the virtual machine we just added.

Here is the answer of the support :

When a new VM is added to a subclient, Commvault automatically will take a full backup for that VM during the next scheduled backup.
 
If, during July and August, the synthetic full backup for the subclient was not triggered or completed, it may be because the schedule detected that a full backup was required for the newly added VMs. As a result, the synthetic full operation was skipped for those months and instead a full backup was taken.

Here is my question for you :

What do you think of this behavior when using plans and not setting up a specific schedule to run the Synthetic full? Do you think it's normal that when you add a virtual machine to a VM group and a full backup runs for it, this will result in there being no full backup for the other virtual machines in the month?

For us, we don't think this behavior is ideal because it breaks the backup cycle and the principle of having a monthly full backup every month for a year.

Thank you