Changes to Jupyter Notebook max buffer size config come undone

I was getting a memory error when I ran a notebook which concatenated several large databases:

MemoryError: Unable to allocate 93.1 MiB for an array with shape (9, 1356250) and data type float64

I applied the solution found here, and it worked (yay!). Basically, I generated the config file, modified NotebookApp.max_buffer_size to double the size, saved it, and voilà, everybody's happy.

However, I tried it again this morning and the notebook started giving me the same error again. I tried reopening and saving the config file, changing the default as well as the buffer size, regenerating the config file and making the same changes, and entering

jupyter notebook --NotebookApp.max_buffer_size=double_value

from the terminal, but nothing seems to work. Any idea what might be going on? Thanks!