The following observation concerns the LREC-Coling 2024 release (camel_morph/official_releases/lrec-coling2024_release/databases/camel-morph-msa):
For nouns, verb-only feats (asp, mod, per) are not generated (as opposed to having value "na"), the same applies to noun-only feats when analysing a verb (cas, form_gen, form_num, rat, sst).