RDBPROD: Rdb 7.3.1 RMU/CONVERT/ROLLBACK may corrupt database - fixed in 7.3.1.1

Using Rdb 7.3.1, an RMU/CONVERT/NOCOMMIT followed at any later time by RMU/CONVERT/ROLLBACK may result in corrupt index metadata.
The problem occurs because some index definitions (stored in RDB$INDICES) are updated to include NODE SIZE and PERCENT FILL.  In some rare cases the old value for RDB$EXTENSION_PARAMETERS cannot be updated (as it would fragment the record) and a new LIST pointer is created.  When ROLLBACK occurs the old metadata cannot locate the old LIST pointer as it was deleted by the normal updating process.

Any attempt to use the index (in a query, SHOW / DROP / EXPORT in SQL, RMU/EXTRACT, etc.) will report errors such as: