The trim-alignment action should use, by default (?), the --p-addfragments option. The reason is outlined in the help text for qiime alignment mafft-add:
--p-addfragments / --p-no-addfragments
Optimize for the addition of short sequence
fragments (for example, primer or amplicon
sequences). If not set, default sequence addition is
used.
The
trim-alignment
action should use, by default (?), the--p-addfragments
option. The reason is outlined in the help text forqiime alignment mafft-add
: