Currently, as advised by MS support, it is a standard D365 process where the general journal is auto posted from the deferral schedule only when it is linked to a project for any transaction type. Also, there is no configuration available to disable or enable this.

This happens despite the setup being disabled for auto posting in the module Subscription billing > Setup > Revenue & expense deferral parameters > General > Recognition > Automatically post general journals > DISABLED.

However, this setup being disabled does not auto post all other general journals from the deferral schedule for transaction types not linked to projects.

The suggestion here, is to have this set up as a configuration option allowing users to either enable or disable posting the general journal from the deferral schedule linked to a project per business requirements accordingly.