Frontend socket connection refused. (no replies)

I have been using HAProxy as a Redis load balancer of sorts within a
Docker container which is part of a simple highly available Redis setup.
I run one instance of HAProxy on each app node and the app communicates
to Redis through the HAProxy instance running on the same node. The only
simple way to make sure this traffic is not crossing machines is to use
a Unix socket instead of TCP. Here is a simple visual explanation of why
sockets are used:

With sockets:
App1 --> Proxy1 ----> (Server1,Server2)
App2 --> Proxy2 --/
App3 --> Proxy3 -/
App4 --> Proxy4 /

Without sockets (TCP - round-robin DNS):
(App1,App2,App3,App4) --> (Proxy1,Proxy2,Proxy3,Proxy4) -->
(Server1,Server2)

So using sockets ensures that I'm not needlessly consuming LAN bandwidth
between the App and Proxy. Due to the way the container scheduler works
there is not a simple way of making sure that the app only uses the
proxy that is on the same machine to prevent it from hitting the network.

Now, to my bug report. I've noticed a few times after letting my test
cluster sit idle for several days that when I come back to use it the
socket no longer works (client reports "Connection refused" error), even
though HAProxy is still running and it does work over TCP. The socket
file is present and is a socket type, it just can't be connected to. If
I restart HAProxy it works, but obviously I don't want it to require
random restarts to stay up. There is nothing in the logs indicating an
error.

Test method:

$ socat - UNIX:/run/magento/redis-cache.sock
2017/02/27 19:45:20 socat[55] E connect(5, AF=1
"/run/magento/redis-cache.sock", 31): Connection refused

Version: 1.6 - just upgraded to 1.7.2 and started testing.

Here is my full HAProxy config:

----------------------------------------------------------------------------------
global
log 127.0.0.1 local0 notice

defaults
mode tcp
log global
timeout client 1h
timeout server 1h
timeout connect 1000

listen stats
bind *:1936
mode http
stats enable
stats hide-version
stats realm Haproxy\ Statistics
stats uri /
stats auth ***:***

frontend redis-unix
bind /run/magento/redis-cache.sock mode 777
default_backend redis

frontend redis-tcp
bind *:6379
default_backend redis

# The tcp-check will ensure that only reachable master nodes are
considered up.
backend redis
balance first
option tcplog
option tcp-check
tcp-check send info\ replication\r\n
tcp-check expect string role:master
default-server inter 5000 downinter 5000 fastinter 1000 rise 2 fall 3
maxconn 256 maxqueue 128
server node1 10.81.128.1:6379 check
server node6 10.81.128.6:6379 check
----------------------------------------------------------------------------------

Thanks!
Colin