Notebook keeps getting stuck on same cell

**Issue**: If I run the entire code at once (using Restart+Run All Cells or just shift+entering instantly), my notebook consistently gets stuck at cell number 5 (even if I change the code in it), which keeps running indefinitely.
**System details**: I am using Jupyter Notebook on Google Cloud Platform on a Ubuntu 18.04 LTS instance. It is a Skylake 8-core, 7.2 GB RAM and 20 GB persistent storage. Jupyter was installed using Anaconda (some modules were installed inside Jupyter Notebook using pip but they were not used until a later cell).
Python 3.7.1
Jupyter Notebook Server 5.7.4
Anaconda3 2018.21
**Workaround**: Wait for each cell to output before running the next cell (which is mostly not ideal).

Start by reproducing the hang with Restart+Run All Cells or rapid Shift+Enter on the reported Ubuntu, Jupyter Notebook, and Python setup, then compare it with waiting for each cell to finish. Focus on why execution stops at cell 5 and verify that running the notebook sequentially completes without an indefinite-running cell.

Written by the indexing model from the issue text.