Production bug - `constraint error when attempting to insert`

[Cinderella-Man]

Observed in live system:

iex(1)> 15:47:20.982 application=hefty module=Hefty.Algos.Naive.Trader [info] Trader(8654) - Rebuy triggered for trade 253938705 bought @ 0.24153000 as price fallen below 0.24128847
iex(1)> 15:47:20.983 application=hefty module=Hefty.Algos.Naive.Leader [info] Rebuy notification received, starting a new trader
iex(1)> 15:47:21.001 application=hefty module=Hefty.Algos.Naive.Trader [info] Starting trader(9241) on symbol XRPUSDT with budget of 11.36414556234
iex(1)> 15:47:21.261 application=phoenix module=Phoenix.Channel.Server [info] Replied phoenix:live_reload :error
iex(1)> 15:47:23.118 application=hefty module=Hefty.Algos.Naive.Trader [info] Trader(9241) - Placing BUY order for XRPUSDT @ 0.24099, quantity: 47.1
iex(1)> 15:48:38.045 application=hefty module=Hefty.Algos.Naive.Trader [info] Trader(9241) received an transaction of 0.40000000 for BUY order 253948392 @ 0.24099000
iex(1)> 15:48:38.751 application=hefty module=Hefty.Algos.Naive.Trader [info] Trader(9241) received an transaction of 33.00000000 for BUY order 253948392 @ 0.24099000
iex(1)> 15:48:39.005 application=hefty module=Hefty.Algos.Naive.Trader [info] Placing SELL order for XRPUSDT @ 0.24195, quantity: 47.1
iex(1)> 15:48:39.812 application=hefty module=Hefty.Algos.Naive.Trader [info] Trader(9241) received an transaction of 13.70000000 for BUY order 253948392 @ 0.24099000
iex(1)> 15:48:40.215 module=gen_server [error] GenServer #PID<0.2938.0> terminating
** (Ecto.ConstraintError) constraint error when attempting to insert struct:

    * trades_pkey (unique_constraint)

If you would like to stop this constraint violation from raising an
exception and instead add it as an error to your changeset, please
call `unique_constraint/3` on your changeset with the constraint
`:name` as an option.

The changeset has not defined any constraint.


    (ecto) lib/ecto/repo/schema.ex:687: anonymous fn/4 in Ecto.Repo.Schema.constraints_to_errors/3
    (elixir) lib/enum.ex:1327: Enum."-map/2-lists^map/1-0-"/2
    (ecto) lib/ecto/repo/schema.ex:672: Ecto.Repo.Schema.constraints_to_errors/3
    (ecto) lib/ecto/repo/schema.ex:274: anonymous fn/15 in Ecto.Repo.Schema.do_insert/4
    (hefty) lib/hefty/trades.ex:70: Hefty.Trades.create_trade/1
    (hefty) lib/hefty/algos/naive/trader.ex:269: anonymous fn/5 in Hefty.Algos.Naive.Trader.handle_info/2
    (ecto_sql) lib/ecto/adapters/sql.ex:874: anonymous fn/3 in Ecto.Adapters.SQL.checkout_or_transaction/4
    (db_connection) lib/db_connection.ex:1415: DBConnection.run_transaction/4
    (hefty) lib/hefty/algos/naive/trader.ex:268: Hefty.Algos.Naive.Trader.handle_info/2
    (stdlib) gen_server.erl:637: :gen_server.try_dispatch/4
    (stdlib) gen_server.erl:711: :gen_server.handle_msg/6
    (stdlib) proc_lib.erl:249: :proc_lib.init_p_do_apply/3
Last message: %Phoenix.Socket.Broadcast{event: "trade_event", payload: %Hefty.Repo.Binance.TradeEvent{__meta__: #Ecto.Schema.Metadata<:loaded, "trade_events">, buyer_market_maker: true, buyer_order_id: 25394839$
iex(1)> 15:48:40.252 application=hefty module=Hefty.Algos.Naive.Leader [info] Leader restarts process as it died
iex(1)> 15:48:40.252 application=hefty module=Hefty.Algos.Naive.Leader [info] Trader found in the list of traders. Removing