'unexpected response' error for http://localhost:3000/api/trace/<runid>/begin

[amygdala]

thanks for working on this project, very interesting!

The app comes up on localhost and appears to be running correctly. However, when I start a nextflow pipeline, I see an error like this:
Unexpected response for request http://localhost:3000/api/trace/V1qM4jciTRlF1JC9/begin
I am using nextflow version 24.04.4.5917.

This is on a mac, and I get that error using either colima or docker desktop.
This is with nf-core pipelines, though I assume that should not make a difference. The docker-compose log output doesn't indicate anything obvious.