Having the same issue with latest stable docker image (sha256:cbc0dfb6487b3e4c58165d0d3e24ae2aa261b0a9732567adf3711f67293b8bc4) when trying to access a remote broker. When trying to access a broker installed in the same host with that of HA, it works fine. I wonder if the TIMEOUT_ACK value of 10 is enough or we need to further increase it.
[UPDATE] It seemed that the problem was on our broker eventually, in the way birth message and last will have been handled. So, it works fine.