At my store all the ETLs rotated the interviews.
Yes, they tried to have the ETL for the department they were hiring for but that wasn't always possible and sometimes it just had to be whoever was there.
With the mass hiring they might have decided to shift one ETLs workload enough to make it possible for them to do all the interviews (it takes a lot of time).\
And if you mean interviews as in they are talking to the seasonals, it could be letting them know who is staying on and who is getting let go.