There are several open issues related to unexpected output when running hugo server. For example:
- https://github.com/gohugoio/hugo/issues/4618
- https://github.com/gohugoio/hugo/issues/6177
- https://github.com/gohugoio/hugo/issues/7960
- https://github.com/gohugoio/hugo/issues/8255
- https://github.com/gohugoio/hugo/issues/8707
- https://github.com/gohugoio/hugo/issues/8863
One or more of these may apply to your scenario.
Over time I have become accustomed to restarting the server when I don’t see what I expect, to the point where I type Ctrl+C hs without even thinking about it (where hs is an alias to hugo server).