The Spirit Realm bears the vast majority of energy—it is the soul of man.
If the soul undergoes changes, the body is the first to be affected.
Changes in the Spirit Realm can swiftly trigger disasters in the Main Material World and are White Tower's primary observation target.
The Sea of Source, although more important, is too remote; its feedback to the Main Material World is quite slow.
Most crucially, humans currently lack an especially good method to directly observe the Sea of Source.
They can only use indirect methods, such as observing the Spirit Realm.
The recent abnormal disturbances in the Spirit Realm are very likely the root cause of anomalies in the Holy Fire.
Its intense fluctuations might have indirectly affected the Sea of Source, leading to issues with the Holy Fire that is rooted in the Sea of Source.
It's like a tower with a shaky foundation facing an earthquake.