I have a bokeh server application with a very thin panel layer of layout statements at the top-level. Panel is being used so I can dynamically add / remove plots interactively with its convenient list-like behavior of layouts.
This all works as expected with bokeh 2.2.3 and panel 0.11.0. However, when upgrading bokeh to the latest revision (bokeh 2.3.1) errors manifest in the JS console log and the plots do not render. I reverted to the most recent minor release (bokeh 2.3.0) and the problem still exists.
My UI initializes with some user widgets and an empty layout of plots. A multi-choice widget enables a user to select which plots to enable (or disable) and a callback adds or removes these from the list of rendered plots.