Problematic tests list (57 rows):
bugs.core_1152_test  Cannot erase a table with check constraints referencing more than a single columns
bugs.core_2712_test  Do not print "invalid request BLR" for par.cpp errors with valid BLR
bugs.core_2783_test  AV using recursive query as subquery in SELECT list and ORDER'ing by them
bugs.core_3690_dialect_3_test  Wrong warning message for ambiguous query
bugs.core_4144_test  Error "context already in use (BLR error)" when preparing a query with UNION
bugs.core_4227_test  Regression: Wrong evaluation of BETWEEN and boolean expressions due to parser conflict
bugs.core_4731_test  Prohibit an ability to issue DML or DDL statements on RDB$ tables (CORE-4731)
bugs.core_4819_test  EXECUTE PROCEDURE's RETURNING_VALUES and EXECUTE STATEMENT's INTO does not check validity of assignments targets leading to bugcheck
bugs.core_4937_test  View/subselect with "union" does not use computed index
bugs.core_5275_test  Expression index may become inconsistent if CREATE INDEX was interrupted after b-tree creation but before commiting
bugs.core_5383_test  Dependencies in Package not recognised
bugs.core_5410_test  Dependencies are not stored when using some type of contructions in subroutines
bugs.core_5481_test  Available indices are not used in some cases if ORDER BY expression is a filtered one
bugs.core_5488_session_idle_test  Timeouts for running SQL statements and idle connections
bugs.core_5659_test  Bad PLAN generated for query on Firebird v3.0
bugs.core_5667_test  Regression in 3.0+: message CTE 'X' has cyclic dependencies appear when 'X' is alias for resultset and there is previous CTE part with the same name 'X' in the query
bugs.core_5921_test  Provide information about Global Commit Number, Commit Number of currently used database snapshot (if any) and Commit Numbers assigned to the committed transactions
bugs.core_5965_test  FB3 Optimiser chooses less efficient plan than FB2.5 optimiser
bugs.core_6095_test  Extend trace record for COMMIT/ROLLBACK RETAINING to allow chaining of transaction ids
bugs.gh_0310_test  System table with keywords
bugs.gh_6802_test  When the statement timeout is set, it causes the lock manager to delay reporting deadlocks until timeout is expired
bugs.gh_6869_test  Domain CHECK-expression can be ignored when we DROP objects that are involved in it
bugs.gh_6941_test  Dummy (always true) conditions may change the join order
bugs.gh_7050_test  Add table MON$COMPILED_STATEMENTS and columns
bugs.gh_7220_test  Dependencies of subroutines are not preserved after backup restore
bugs.gh_7331_test  Cost-based choice between nested loop join and hash join
bugs.gh_7398_test  Worst plan sort created to execute an indexed tables
bugs.gh_7426_test  Ensure the DDL trigger requests are cached
bugs.gh_7466_plans_tracking_test  Add COMPILE trace events - ability to see execution plan of every PSQL statement.
bugs.gh_7466_test  Add COMPILE trace events for procedures/functions/triggers
bugs.gh_7598_test  Wrong detection of must-be-delimited user names
bugs.gh_7804_test  The partial index is not involved when filtering conditions through OR.
bugs.gh_7904_test  More realistic cardinality adjustments for unmatchable booleans // FB5 bad plan for query
bugs.gh_7921_test  FB5 uses PK for ordered plan even if less count of fields matching index exists
bugs.gh_8077_test  Error "Too many recursion levels" does not stop execuition of code that uses ON DISCONNECT trigger (FB 4.x+)
bugs.gh_8109_test  Plan/Performance regression when using special construct for IN in FB5.x compared to FB3.x
bugs.gh_8161_test  Cardinality estimation should use primary record versions only
bugs.gh_8278_test  Avoid index lookup for a NULL key if the condition is known to always be FALSE in this case
bugs.gh_8291_test  NULLs should be skipped during index navigation when there's no lower bound and matched conditions are known to ignore NULLs
bugs.gh_8386_test  Crash when creating index on table that uses UDR and ParallelWorkers > 1
bugs.gh_8434_test  Fix implicitly used collations after ALTER DOMAIN
bugs.gh_8488_test  MIN/MAX aggregates may badly affect the join order in queries with mixed INNER/LEFT joins
bugs.gh_8661_test  Strange output from SHOW DEPENDENCIES command on 6.0
bugs.gh_8851_test  'Internal error' when calling outer procedure after deleting unused result variable from inner procedure
bugs.gh_8926_test  Indexes may not be used for multiple ORed conditions containing both field and non-field references
bugs.gh_8950_test  ALTER TABLE <T> ALTER <INDEXED_NON_TEXTUAL_COL> TYPE VARCHAR(nnnn) causes column to be non-updatable state
functional.arno.optimizer.test_opt_inner_join_05  INNER JOIN join order LIKE and STARTING WITH
functional.basic.isql.test_02  ISQL - SHOW SYSTEM TABLES
functional.basic.isql.test_03  ISQL - SHOW SYSTEM parameters
functional.gtcs.test_computed_fields_13  Computed fields
functional.gtcs.test_misplaced_collation_in_extracted_metadata  Misplaced collation when extracting metadata with isql
functional.gtcs.test_returning_01  Test of RETURNING clause: INSERT, UPDATE, MERGE.
functional.metacache.test_95996928  Avoid infinite wait due to non-optimum plan & use of read committed no record version transaction for DML by ISQL
functional.table.alter.test_05  ALTER TABLE - ALTER - TO
functional.tabloid.test_8f728e63  Fix cardinality estimations for semi/anti joins
functional.trigger.alter.test_alter_dml_basic  ALTER TRIGGER - basic checks for DML triggers
functional.trigger.database.test_transactioncommit_01  Trigger on commit transaction. See also CORE-645

This list is the same for:
6.0.0.2001 2026.06.08 77c2e7d5  CS
6.0.0.2002 2026.06.10 b408a059  CS