Hi @jbednar,
I tried debugging this issue. It looks that the execution time for nbconvert on aarch64 is longer than what it takes on x86. I increased the timeout to twice in /root/miniconda/envs/test/lib/python3.7/site-packages/nbconvert/preprocessors/execute.py after line no. 552(deadline = deadline * 2) and the test case is passing successfully.
Can you suggest any resolution for it?