Unhandled Error - builtins.KeyError: 0

Using version 1.9 of haas-proxy. I noticed in logs:

Jun 22 19:41:50 turris haas-proxy-start[4407]: 2020-06-22T21:41:50+0200 [SSHService b'ssh-connection' on SSHServerTransport,2448,212.36.91.156] Unhandled Error
Jun 22 19:41:50 turris haas-proxy-start[4407]:  Traceback (most recent call last):
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/internet/tcp.py", line 243, in doRead
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/internet/tcp.py", line 249, in _dataReceived
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/conch/ssh/transport.py", line 703, in dataReceived
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/conch/ssh/transport.py", line 728, in dispatchMessage
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:  --- <exception caught here> ---
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/python/log.py", line 103, in callWithLogger
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/python/log.py", line 86, in callWithContext
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/python/context.py", line 122, in callWithContext
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/python/context.py", line 85, in callWithContext
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/conch/ssh/service.py", line 45, in packetReceived
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/conch/ssh/connection.py", line 295, in ssh_CHANNEL_EOF
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:  builtins.KeyError: 0
Jun 22 19:41:50 turris haas-proxy-start[4407]: 
Jun 22 19:41:50 turris haas-proxy-start[4407]: 2020-06-22T21:41:50+0200 [SSHService b'ssh-connection' on SSHServerTransport,2448,212.36.91.156] Unhandled Error
Jun 22 19:41:50 turris haas-proxy-start[4407]:  Traceback (most recent call last):
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/internet/tcp.py", line 243, in doRead
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/internet/tcp.py", line 249, in _dataReceived
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/conch/ssh/transport.py", line 703, in dataReceived
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/conch/ssh/transport.py", line 728, in dispatchMessage
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:  --- <exception caught here> ---
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/python/log.py", line 103, in callWithLogger
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/python/log.py", line 86, in callWithContext
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/python/context.py", line 122, in callWithContext
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/python/context.py", line 85, in callWithContext
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/conch/ssh/service.py", line 45, in packetReceived
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:    File "/usr/lib/python3.7/site-packages/twisted/conch/ssh/connection.py", line 308, in ssh_CHANNEL_CLOSE
Jun 22 19:41:50 turris haas-proxy-start[4407]:      
Jun 22 19:41:50 turris haas-proxy-start[4407]:  builtins.KeyError: 0