Docker postgres container instability and password fail error

I'm running Docker 3.6.0 on a Mac. I only run one container, which is a postgres 9.6 instance. Over the last few months, I've noticed the stability of the postgres instance get worse and worse and eventually I just restart the container multiple times a day and then it keeps crashing later on.

If I stop Docker completely, then start it again, I run "container logs " (without even starting any container) and it very rapidly logs this line repeatedly:

FATAL:  password authentication failed for user "postgres"
DETAIL:  Password does not match for user "postgres".
    Connection matched pg_hba.conf line 95: "host all all all md5"

I've tried to stop any programs that would be making a connection to this database (that I know of) and yet I still keep seeing this logged in fast succession.

I'm not totally sure if this logging is related to my problem with stability. Ultimately, I would like for the postgres instance to not crash all the time.

Docker is running with port 5432 mapped from my Mac to the docker instance (same port).

If I look within the container at: "/var/lib/postgresql/data/pg_hba.conf", I see it ends with:

host all all all md5