Be careful when the parallel import feature is enabled for a specific system. One automation per file is needed. So you need to have at least one for each of the following:
*_LTAPPIDGT_lastactivation.csv.gz
*_LTAPPIDGT_lastactivation.csv.gz
*_LTAPPIDGT_lastactivation.csv.gz
If you use custom fields then you need to create one per each one.