Checkpoint cleanup avoids reading any internal pages from disk into memory when the internal pages aggregated stop durable timestamp is zero. This can cause problems when a truncate/remove operation is performed with by a non timestamped transaction.
The obsolete pages without a timestamp information are never load back into the memory to free the disk space.
Currently, we do not have proper aggregated time information to decide a page needs to be read into the cache or not. The solution to this problem is read every internal page into memory.