Missing articles – KeyError: 'filename'

[encukou]

Some articles are missing, for example:

ERROR: Could not process ./2006-08-09_co-prinesl-podzim.md

  | KeyError: 'filename'

This appears to be due to this change in Danube Delta: honzajavorek/danube-delta@5ede6ef

What worries me is that the build succeeded with missing articles.