I was running into an issue with having to run a second composer install to install the simplesamlphp/simplesamlphp-assets-base package which has the base assets. This package contained the javascript to handle the post request for logout in my case. There could be other scenarios that require this package.
I worked around having to manually run the second composer install by adding the following as a post-install-cmd in composer.json
"composer install --no-scripts --no-interaction"
I am adding this here so that this helps somebody else. Maybe there is also something that I am missing in how I am doing this.
Fixed
4.0
Documentation
Yes, annoying, but not something we can do something about. See https://github.com/simplesamlphp/simplesamlphp/issues/1853 for the upstream issue.
Automatically closed - issue fixed for 2 weeks with no activity.