On distros which don't apply any downstream theming (i.e., Debian and Arch I've seen this), the default indicator layout doesn't look good. The hostname shows up about 2/3rds of the way across from the right edge of the screen. Having it either centered or aligned on the left edge of the screen would look much better.

I'm not sure whether an indicator that should be there just isn't loading, or if it would be better to look into how the spacers are handled.

I can recreate the defaults with

indicators=~spacer;~spacer;~host;~spacer;~session;~a11y;~clock;~power

Deleting either both spacers to move the hostname all the way to left, or setting it up with

indicators=~host;~spacer;~clock;~spacer;[all the other stuff]

would also seem to fix it (I think some distros use a similar config downstream).