SYMPTOM:
Subscriptions are not using pre-existing caches and instead re-execute against the warehouse in Strategy 10.x.
CAUSE:
The governing subcategory "Subscription Execution" was introduced in Strategy 10.x and is located under Project Configuration > Caching as shown below.

This governing subcategory contains three options that can disable the use of caching for subscriptions:
ACTION:
If caches are not being used for subscriptions, these governing settings may be enabled/checked. Disable the appropriate options to re-enable cache usage.