Side conversation ticket (child ticket) problem

While using side conversation tickets (child tickets) there is a problem that the child ticket doesn't open automatically, when the requester adds a new comment to it from the mother ticket. This should naturally behave like "normal tickets", but it doesn't.

We are currently trying out a trigger that opens Pending tickets when the ticket is updated by  a person who is an agent. However, creating a trigger for this workflow is not ideal, and definitely this should work by default without any triggers. We are not sure yet if this trigger will work ideally in all cases. Thus we hope that Zendesk will develop the child ticket feature futher.

Below is the response we got from Zendesk support, concerning the issue:

This is Dane from Zendesk Advocacy Team and I'm here to help regarding your inquiry on child tickets.I've been playing around with this workflow in my test account all day, and have been coming up short in delivering something grand. I did find a slack thread from last month that has a software engineer talking about how in the future, we plan on having trigger conditions and actions that can work with the parent>child ticket relationship, but at this time, there is no native feature to have an update to the parent ticket reflect in the child ticket.
I DO see some alternative solutions to achieve what you are looking for, which we can not support, but I will put on your radar anyway. Using ZIS to achieve (https://developer.zendesk.com/documentation/integration-services/getting-started/understanding-zis/) the Parent status change>Child status change you're looking for. It looks like it might be some heavy lifting, but this would do it according to the thread I mentioned previously.
I also tried to utilize webhook but it seems the parameters for side conversations is only for open state and closed state which will only be triggered when the Side Conversation has been "Mark as Done". There's no parameter for the actual ticket status.
Would you mind posting your use case to our Feedback on Support topic<https://support.zendesk.com/hc/en-us/community/topics/200132066>? This is to help get more visibility and votes on the idea. Then, others can share their use cases to further drive demand for that feature and eventually have the implementation prioritized.