Register fails with empty bio

[info] POST /api/account/register.json
[debug] Processing with Pleroma.Web.TwitterAPI.Controller.register/2
  Parameters: %{"_format" => "json", "email" => "href@random.sh", "fullname" => "test", "nickname" => "ferh", "password" => "[FILTERED]", "username" => "ferh"}
  Pipelines: [:api]
[info] Sent 500 in 120ms
[error] #PID<0.555.0> running Pleroma.Web.Endpoint (cowboy_protocol) terminated
Server: pleroma-test-0512:4008 (http)
Request: POST /api/account/register.json
** (exit) an exception was raised:
    ** (FunctionClauseError) no function clause matching in Regex.scan/3
        (elixir) lib/regex.ex:409: Regex.scan(~r/@[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]*@?[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*/u, nil, [])
        (pleroma) lib/pleroma/formatter.ex:23: Pleroma.Formatter.parse_mentions/1
        (pleroma) lib/pleroma/user.ex:810: Pleroma.User.parse_bio/2
        (pleroma) lib/pleroma/web/twitter_api/twitter_api.ex:135: Pleroma.Web.TwitterAPI.TwitterAPI.register_user/1
        (pleroma) lib/pleroma/web/twitter_api/twitter_api_controller.ex:283: Pleroma.Web.TwitterAPI.Controller.register/2
        (pleroma) lib/pleroma/web/twitter_api/twitter_api_controller.ex:1: Pleroma.Web.TwitterAPI.Controller.action/2
        (pleroma) lib/pleroma/web/twitter_api/twitter_api_controller.ex:1: Pleroma.Web.TwitterAPI.Controller.phoenix_controller_pipeline/2
        (pleroma) lib/pleroma/web/endpoint.ex:1: Pleroma.Web.Endpoint.instrument/4
        (phoenix) lib/phoenix/router.ex:278: Phoenix.Router.__call__/1
        (pleroma) lib/pleroma/web/endpoint.ex:1: Pleroma.Web.Endpoint.plug_builder_call/2
        (pleroma) lib/plug/debugger.ex:122: Pleroma.Web.Endpoint."call (overridable 3)"/2
        (pleroma) lib/pleroma/web/endpoint.ex:1: Pleroma.Web.Endpoint.call/2
        (plug) lib/plug/adapters/cowboy/handler.ex:16: Plug.Adapters.Cowboy.Handler.upgrade/4
        (cowboy) /root/pleroma/deps/cowboy/src/cowboy_protocol.erl:442: :cowboy_protocol.execute/4