ipypopout solara content not displaying properly

[havok2063]

I am seeing strange behavior when using Solara to embed Jdaviz into a front-end app. When the button to popout Jdaviz into a browser window is clicked, the application fails to display. Instead the following content message is displayed: A widget with mount-id="solara-main" should go here. As far as I can tell, I have the correct data-base-url and data-voila-host attributes set on the html body.

This is only seen in my production environment, which is solara app mounted into a fastapi app, deployed behind a dual-proxy nginx setup at '/valis/solara'. data-base-url is set to the nginx location path of the solara app, and data-voila-host is set to the main domain (the first proxy). I cannot reproduce this locally, when running in dev mode, or when duplicating the production setup with fake domains, so I'm not sure what the issue could be. It's seen using ipypopout == 1.4, jdaviz==3.10.3, and solara>=1.37, but also seen with earlier and later versions of solara and ipypopout.

If desired I can provide some example code, but I'm not sure it will reproduce the error. What triggers this message? Any thoughts on what could be causing this?