Custom socket repl accept function seems being ignored

[onetom]

When I start lumo with a bogus socket repl accept function

$ lumo -n '{"port":5559, "accept":"XXX"}'
Lumo 1.9.0-alpha
ClojureScript 1.10.238
Node.js v9.10.1
...
Lumo socket REPL listening at localhost:5559.
cljs.user=>

connecting to it won't throw an exception

$ nc localhost 5559
Lumo 1.9.0-alpha
ClojureScript 1.10.238
Node.js v9.10.1
...
cljs.user=> 123
123
cljs.user=>

like it did in earlier versions

lumo -n '{"port":5559, "accept":"XXX"}'
Lumo 1.8.0
ClojureScript 1.9.946
Node.js v9.2.0
...
Lumo socket REPL listening at localhost:5559.
cljs.user=> 

when upon running nc localhost 5559 it throws this error:

cljs.user=> <embedded>:463
cljs.core.symbol.cljs$core$IFn$_invoke$arity$1=function(a){if(a instanceof cljs.core.Symbol)return a;var b=a.indexOf("/");return 1>b?cljs.core.symbol.cljs$core$IFn$_invoke$arity$2(null,a):cljs.core.symbol.cljs$core$IFn$_invoke$arity$2(a.substring(0,b),a.substring(b+1,a.length))};
                                                                                                             ^

TypeError: Cannot read property 'indexOf' of null
    at Function.cljs.core.symbol.cljs$core$IFn$_invoke$arity$1 (<embedded>:463:110)
    at Object.lumo.repl.ns_symbol (<embedded>:6680:514)
    at Object.lumo.repl.run_accept_fn (<embedded>:6682:57)
    at Lt ([eval]:1:31935)
    at Qe ([eval]:1:24855)
    at Server.dn.createServer ([eval]:1:25116)
    at Server.emit (events.js:159:13)
    at TCP.onconnection (net.js:1583:8)

Running it with correct parameters

$ lumo -c src -n '{"port":5559, "accept":"myapp.repl/accept"}'

works on Lumo 1.8.0, but not on 1.9.0-alpha:

$ nc localhost 5559

Hello friend.
You gave me the following args: ({"foo" 2})

when src/myapp/repl.js is:

(ns myapp.repl)

(defn accept [socket & args]
  (.end socket (str "\nHello friend.\nYou gave me the following args: " args "\n\n")))