CSV Writer stuck at 99%

I have a CSV Writer that used to work, but now it is sticking at 99% after switching the target directory to a new level. 2.2M records and about 130 columns. No errors are thrown. I tried different encoding settings, but no joy.

If I create a table-writing node, it completes the write to the same directory without issue.

What are potential issues that could cause a CSV Write to fail when a KNIME table reader succeeds? I need to push this out into CSV (or something else PowerBI can read).