If the materialization of a deferred table is part of a transaction that gets rolled back, SAP ASE does not roll back any page allocations that have been performed for the deferred table.
create table im_not_here_yet with deferred_allocation go begin tran t1 go insert into deferred table ... go rollback tran t1
insert materializes the im_not_here_yet, table, then inserts a value. Although the rollback tran removes the value from the table, the page allocation is not rolled back, so the table remains materialized and is no longer a deferred table.