Durations in CSVs break on refresh

[HactarCE]

1. Make a new file
2. Drag this CSV file onto the grid at A1
3. Note that durations import correctly
4. Put this Python code at I1 and run it:

import numpy as np
import pandas as pd

pd.DataFrame(np.vectorize(lambda s: str.strip(s) if isinstance(s, str) else s)(np.array(cells((1,1),(7,601)))))

6. Refresh

Expected behavior: durations have their original values

Actual behavior: all durations have the value 0s