here's an issue that I think a couple of other instances have run into: https://github.com/ubergeek77/Lemmy-Easy-Deploy/issues/26 (it's not from the lemmy-ansible repo but I think this developer tries to follow lemmy-ansible's docker file quite closely)
from a glance it seems to involve the /etc/hosts file interacting with docker dns, causing lemmy-ui to fail when finding the site icon (so if you haven't set that then you probably won't encounter this issue)
edit: okay, I think https://monyet.cc/pictrs/image/9af04c84-4810-436c-9263-b550eb2de176.png is the site icon, so you have it set