What architectural challenges arise from running SAP systems across on-premise and cloud simultaneously?

Beyond the obvious network connectivity concern, hybrid operation introduces several deeper architectural tensions that a senior architect needs a deliberate strategy for, not just ad hoc point solutions.

• Data consistency — keeping master data synchronized between on-premise and cloud systems without introducing conflicting "sources of truth."
• Identity and access management — a single user identity needs to work consistently across systems with fundamentally different underlying authentication mechanisms.
• Monitoring and operations — unified visibility into system health and performance across environments with different native tooling.
• Security boundary management — the network perimeter is no longer a single, clean boundary, requiring a more distributed security model.

Each of these typically needs its own deliberate architectural pattern (a master data hub, a federated identity provider, unified monitoring tooling) rather than being solved incidentally as individual systems are migrated one at a time.