Plotting multiple cells in a single plot

Hi everyone,
I have been using the nbagg tool in jupyter to plot data for a year or two without issue. However, I am now running into the opposite problem that most people have- I would like to plot multiple lines of data into a single graph. Usually, just keeping the graph active and executing the multiple lines does the trick- but no such luck lately. I haven't changed the imported packages at all. Any idea how to fix it?
Thank you

Start by reproducing the reported behavior with the nbagg tool in Jupyter, using multiple plotting commands intended to appear in one graph. Check whether the imported packages and execution environment affect the result; done means multiple data lines render together in a single plot.

Written by the indexing model from the issue text.