This hit me and I tracked it down, and created this account to answer. It has to do with the sed in entrypoint.sh in the container. It uses _ as a separator:
sed -i -E "s_^TZ=.*_TZ=\"${TZ}\"_" "/opt/omd/sites/$CMK_SITE_ID/etc/environment"
and it breaks if you have a _ in your timezone, like America/New_York or America/Los_Angeles and probably others.
I was using Los_Angeles and switched to PST8PDT (had to edit that environment file manually) and that fixed it.
That would explain why it happens across versions for some people, and never for others, and only in the container release.