Starting with the release of Strategy ONE (March 2024), dossiers are also known as dashboards.
SYMPTOM:
It's impossible to schedule to refresh the data import cubes which are created within a VI Dashbaord as the cubes are "Managed by the system" and cannot be located in file system.

STEPS TO REPRODUCE:
CAUSE:
This is a known limitation in Strategy.
ACTION:
Currently this issue is being reviewed by Strategy for a potential code fix on an upcoming Strategy release.
WORKAROUND:
Create data import cubes as standalone objects instead creating in VI, and the cube can be located from file system and able to be scheduled refresh.
SOLUTION:
Upgrade to Strategy 2019 to resolve this issue. The video below shows how to schedule a refresh of date import cubes built inside a dossier using Strategy 2019.