How to shut down engine on Windows 10?

I have tried several different methods to shut down the Matlab engine, before logging out of a Jupyter notebook running a Julia 1.3 kernel in Firefox on a Windows-10 box. (I never explicitly launch the engine, just use mat"" commands.) When I restart the notebook (and the Julia kernel), then import MATLAB.jl, my Matlab workspace variables and path from the previous session are all still there. And Windows TaskManager shows a MATLAB process running. Of course I can just use TaskManager to "End task" - but that seems rather indirect.

The only way I have found to shut down the engine within the notebook is to do

MATLAB.mat"quit"

which results in

MATLAB.MEngineError("invalid engine session (err = 1)")

followed by

MATLAB.close_default_msession()
MATLAB.restart_default_msession()

which crashes the Julia kernel. Sometimes the kernel restarts on its own, other times I need to use the menu Kernel->Restart.

Please advise.

Start by reproducing the shutdown sequence in a Jupyter notebook on Windows 10, focusing on MATLAB.mat"quit", MATLAB.close_default_msession(), and MATLAB.restart_default_msession(). Confirm whether the MATLAB process can be terminated without an invalid engine error or Julia kernel crash.