Error while running feature-table heatmap in 2019.1 version

Hmm, I just ran the following command on the files you sent me:

qiime feature-table heatmap \
  --i-table collapsed_table_level6.qza \
  --m-metadata-file metadata_forum.tsv \
  --m-metadata-column exacerb_kategori \
  --p-normalize \
  --p-cluster features \
  --o-visualization heatmap-genus.qzv \
  --verbose

I tried in 2019.1 and the development version of 2019.4 and it ran successfully to completion.

I wonder if your environment has had some modifications, specifically around some of the dependencies... Can you run conda list and paste the results here?