The ss wt pages read into cache statistic is wrong in disagg.

The FTDC except here shows that it is consistently almost zero in a workload where the block manager is reading 1000s of blocks per second. Almost all block manager reads are from page requests. So something is clearly wrong here.

The cache number of pages read that had deltas attached statistic almost perfect tracks block manager reads. So possibly we are not counting reads that have deltas as pages read into the cache.