Explanation

When multiple policies are applied to groups that users are a member of, only the highest priority (lowest number) policy applies.
In this case, the Engineering users are assigned two device type policies (the default policy and the priority 2 policy). The priority 2 policy has a higher priority than the default policy so the Engineers' allowed platform is Android only.
The engineers have two device limit restrictions policies applied them. The priority1 policy is a higher priority than the priority2 policy so the priority1 policy device limit (15) applies.
Reference:
https://docs.microsoft.com/en-us/intune/enrollment/enrollment-restrictions-set