I haven't looked into in great depth, but for me it seems to hang when the site refreshes after a file change (so that is when something like

vite build --watch

has regenerated the files to the RCL folder and visualt studio's browser link has triggered a reload of the page. if i kill the browser and just reload the page its fine. and like above it seems to happen a lot less in chrome. so not yet got a clean handle on what can reproduce it. 😦