The workaround is to remove the additional entries inside the HIBERNATE_UNIQUE_KEY table directly from the database.

1. Shutdown Bamboo.

2. Run the following SQL query in your Bamboo database:

   select * from HIBERNATE_UNIQUE_KEY;

3. This will return something like this (values may vary):

   select * from HIBERNATE_UNIQUE_KEY;
    next_hi 
   ---------
       3997
         13
       3997
       3997
       3997
       3999
   (6 rows)

4. Choose the higher value from the result of the previous SQL query and run the following delete:

   (!) Always backup your database before applying any changes.

   delete from HIBERNATE_UNIQUE_KEY where next_hi < 3999; 

   This will delete all values lower than 3999 from the next_hi column inside the HIBERNATE_UNIQUE_KEY table.

5. Run the SQL query from Step 2 again to make sure there's only one value now:

   select * from HIBERNATE_UNIQUE_KEY;
    next_hi 
   ---------
       3999
   (1 row)

6. Start Bamboo.