setval: value -2 is out of bounds for sequence "events_backfill_stream_seq"

[Half-Shot]

When running develop against a host previously on 1.20.0, I see:

2020-09-24 15:20:02,569 - synapse.storage.prepare_database - 379 - INFO - None- Applying schema deltas for v58
2020-09-24 15:20:02,570 - synapse.storage.prepare_database - 474 - INFO - None- Applying engine-specific schema 58/07add_method_to_thumbnail_constraint.sql.postgres
2020-09-24 15:20:02,573 - synapse.storage.prepare_database - 466 - INFO - None- Applying schema 58/10_pushrules_enabled_delete_obsolete.sql
2020-09-24 15:20:02,575 - synapse.storage.prepare_database - 466 - INFO - None- Applying schema 58/14events_instance_name.sql
2020-09-24 15:20:02,578 - synapse.storage.prepare_database - 474 - INFO - None- Applying engine-specific schema 58/14events_instance_name.sql.postgres
2020-09-24 15:20:02,583 - twisted - 250 - ERROR - - Traceback (most recent call last):
2020-09-24 15:20:02,584 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/runpy.py", line 193, in _run_module_as_main
2020-09-24 15:20:02,584 - twisted - 250 - ERROR - -     "__main__", mod_spec)
2020-09-24 15:20:02,584 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/runpy.py", line 85, in _run_code
2020-09-24 15:20:02,584 - twisted - 250 - ERROR - -     exec(code, run_globals)
2020-09-24 15:20:02,584 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/app/homeserver.py", line 695, in <module>
2020-09-24 15:20:02,585 - twisted - 250 - ERROR - -     main()
2020-09-24 15:20:02,585 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/app/homeserver.py", line 690, in main
2020-09-24 15:20:02,586 - twisted - 250 - ERROR - -     hs = setup(sys.argv[1:])
2020-09-24 15:20:02,586 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/app/homeserver.py", line 386, in setup
2020-09-24 15:20:02,586 - twisted - 250 - ERROR - -     hs.setup()
2020-09-24 15:20:02,586 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/server.py", line 251, in setup
2020-09-24 15:20:02,587 - twisted - 250 - ERROR - -     self.datastores = Databases(self.DATASTORE_CLASS, self)
2020-09-24 15:20:02,587 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/storage/databases/__init__.py", line 59, in __init__
2020-09-24 15:20:02,587 - twisted - 250 - ERROR - -     db_conn, engine, hs.config, databases=database_config.databases,
2020-09-24 15:20:02,587 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/storage/prepare_database.py", line 135, in prepare_database
2020-09-24 15:20:02,587 - twisted - 250 - ERROR - -     databases=databases,
2020-09-24 15:20:02,588 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/storage/prepare_database.py", line 475, in _upgrade_existing_database
2020-09-24 15:20:02,588 - twisted - 250 - ERROR - -     executescript(cur, absolute_path)
2020-09-24 15:20:02,588 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/storage/prepare_database.py", line 610, in executescript
2020-09-24 15:20:02,589 - twisted - 250 - ERROR - -     execute_statements_from_stream(txn, f)
2020-09-24 15:20:02,589 - twisted - 250 - ERROR - -   File "/usr/local/lib/python3.7/site-packages/synapse/storage/prepare_database.py", line 615, in execute_statements_from_stream
2020-09-24 15:20:02,589 - twisted - 250 - ERROR - -     cur.execute(statement)
2020-09-24 15:20:02,589 - twisted - 250 - ERROR - - psycopg2.errors.NumericValueOutOfRange: setval: value -2 is out of bounds for sequence "events_backfill_stream_seq" (1..9223372036854775807)
2020-09-24 15:20:02,590 - twisted - 250 - ERROR - -