"error submitting request: error reading response: unexpected EOF" using forward socks proxy in pappy-proxy v0.3.1

[JollyFrogs]

In Pappy Proxy 0.3.1, when using a forward socks proxy, the following error is given in the browser:
"error submitting request: error reading response: unexpected EOF"

To reproduce:
Create a socks proxy using ssh -D (works in Burp, and in Pappy proxy 0.2.14)

$ ssh -q -f -N someuser@somehost -p 22 -L 127.0.0.1:2222:REMOTEIP:22
$ ssh -q -f -N -D 127.0.0.1:9050 -p 2222 someuser@127.0.0.1
$ netstat -nl | grep 9050
tcp 0 0 127.0.0.1:9050 0.0.0.0:* LISTEN
$ cat config.json
{
"listeners": [
{"iface": "127.0.0.1", "port": 8080}
],
"proxy": {"use_proxy": true, "host": "127.0.0.1", "port": 9050, "is_socks": true}
}
$ ~/pappy-proxy-master/start
pappy >

Note, that when using the pappy proxy with a forward proxy, the error appears in the browser:
"error submitting request: error reading response: unexpected EOF"

This error does not show up in Pappy proxy 0.2.14 and also not in Burp, and in those two tools, the SSH forward proxy works without any issue.