A standby can write to the ingest table, but not the stable table.

If a standby does a cursor->modify, the modify will go to the ingest table even though the base value is in the stable table. If the standby updates its checkpoint and the base value changes, the modify doesn't make sense any more.

We should verify that the above scenario can't happen, probably by either verifying that modify doesn't work for layered cursors, or by making sure the base value is somewhere in the update chain for the value in the ingest table.