I am not certain that I follow your listing. But I think you are saying that you are setting up virtual chassis links by running most of the switche members back to the same common switch. If so this would not be the expectd topology.
The virtual chassis links should be in a ring topology where each switch connects to two other switches. If the ring is not possible it can be an open chain but would have less resilience in cable loss scenarios.
to see the current status and troubleshoot the VC setup run through the steps outline here.
https://kb.juniper.net/InfoCenter/index?page=content&id=KB21064
best practices examples
https://www.juniper.net/us/en/local/pdf/implementation-guides/8010018-en.pdf