The Teradata Database channel includes discussions around advanced Teradata features such as high-performance parallel database technology, the optimizer, mixed workload management solutions, and other related technologies.
Any two operations on the same system that will compete for resources will always have the potential for impact, even assuming you aren't backuping up objects that are also being targeted by loads at the same time (which you shouldn't).
Teradata Online backups don't use HUT locks however they require read locks to create the subtables
ETL jobs that create and distroy objects rather than reusing load database/tables can create conflicts within DBC which Online backups need access to DBC tables.
Online backups generate more I/O than standard backups because the before image of altered rows need to be copied to the subtable which is backed up once the base object is backed up.