IDO isn't updating host contacts if new contact is added to contact group

Describe the bug

I noticed missing contacts of hosts and services in the icingaweb2 monitoring module.

If I send a test notification, the missing contacts get notified.
If I click on the contact group the missing contacts are listed.
I had a look in the IDO _host_contacts table and noticed only the displayed contacts are present for the host.

After adding a note to the host and deploying with the director the missing contacts appeared.

To Reproduce

1. note contacts of host or service with a contact group in the icingaweb2 monitoring module
2. add new user to user group in director
3. deploy
4. note contacts of host or service with a contact group in the icingaweb2 monitoring module
5. change something on host
6. deploy
7. note contacts of host or service with a contact group in the icingaweb2 monitoring module

Expected behavior

Changes to members of contact groups get updated in the icingaweb2 monitoring module's contacts without requiring a change to the host or service object.

Your Environment

Include as many relevant details about the environment you experienced the problem in

• Icinga2 version: r2.14.2-1
• OS: AlmaLinux 8.9
• Enabled features: api checker gelf icingadb ido-mysql influxdb mainlog notification
• Icinga Web 2 version: 2.12.1
• monitoring module version: 2.12.1

Additional context

Because of our issues with icingadb like ref/IP/48748 a fix in the legacy monitoring module would be very welcome.

Start by reproducing the contact-group membership change and inspect the IDO _host_contacts table alongside the icingaweb2 monitoring module contacts view. Trace how deploying a user-group change differs from deploying a host or service change; done means newly added group members appear without modifying the host or service object.