OCaml exception found in ocsigenserver logs

[MdeLv]

Debian 10
OCaml 4.07.1
ocsigenserver.2.16.0 (with ocsigen-start.2.16.1)
Makefile.os : RUN_DEBUG ?= "-v" (minimum verbosity)

==========================================
Here is a stdlib.ml raised exception found in the ocsigenserver logs.
It occurred after a non significant browser inactivity (a few seconds).
It has no visible impact from the website user. So it should be handled correctly.

It it normal to find it in ocsigenserver logs?
Can it be fixed in order to clean up logs?

DETAILS
(I don't know how to make that stuff foldable)

ocsigenserver: main: Unexpected exception in Server.wait_connection (handle connection): (Invalid_argument Lwt.wakeup)
ocsigenserver: main: backtrace:
ocsigenserver: main: Raised at file "stdlib.ml", line 34, characters 25-45
ocsigenserver: main: Called from file "ocsigen_http_com.ml", line 158, characters 2-33
ocsigenserver: main: Called from file "ocsigen_server.ml", line 836, characters 4-35
ocsigenserver: main: Called from file "src/core/lwt.ml", line 2048, characters 23-28

According the code of stdlib.ml, it's an "index out of bounds" array error:

$ cat stdlib.ml
let invalid_arg s = raise(Invalid_argument s) (* line 34 *)

$ cat ocsigen_http_com.ml
let abort conn =
  Lwt.wakeup (snd conn.closed) (); (* line 158 *)
  Lwt_ssl.abort conn.fd Aborted

$ cat ocsigen_server.ml
  let handle_write_errors e =
    begin match e with
      | Lost_connection e' ->
        warn sockaddr ("connection abruptly closed by peer ("
                       ^ Printexc.to_string e' ^ ")")
      | Ocsigen_http_com.Timeout ->
        warn sockaddr "timeout"
      | Ocsigen_http_com.Aborted ->
        dbg sockaddr "writing thread aborted"
      | Ocsigen_stream.Interrupted e' ->
        warn sockaddr ("interrupted content stream ("
                       ^ Printexc.to_string e' ^ ")")
      | _ ->
        Ocsigen_messages.unexpected_exception e "Server.handle_write_errors"
    end;
    Ocsigen_http_com.abort receiver; (* line 836 *)
    Lwt.fail Ocsigen_http_com.Aborted

$ cat lwt/core/scr/lwt.ml
let callback p_result =
        match p_result with
        | Fulfilled _ as p_result ->
          let State_may_now_be_pending_proxy p'' = may_now_be_proxy p'' in
          let p'' = underlying p'' in

          let State_may_have_changed p'' =
            resolve ~allow_deferring:false p'' p_result in
          ignore p''

        | Rejected exn ->
          current_storage := saved_storage;

          let p' = try h exn with exn -> fail exn in  (* line 2048 *)
          let Internal p' = to_internal_promise p' in

          let State_may_now_be_pending_proxy p'' = may_now_be_proxy p'' in
          let p'' = underlying p'' in

          let State_may_have_changed p'' =
            make_into_proxy ~outer_promise:p'' ~user_provided_promise:p' in
          ignore p''

[MdeLv]

Can you have a look at that issue?
Is it a normal message?
Thanks.

[glondu]

HTTP handling changed significantly in 3.0.0. Can you retry with a recent ocsigenserver?