Hi there, I’m facing the same “unexpected referrers!” error. I can start my app in Spyder with .show() without error but in the terminal using panel serve I get the mysterious message and the app does not run. Before updating Panel and Geoviews and bokeh (new version 2.3.3) it runs in the terminal like charme. But I did not deployed the app yet. Therefore I porobably didn’t notice the memory leak.