Why is my tenant's employer suddenly paying their rent?

[Samuel Kissick]

Hello! 

One of my tenant's recently asked for an invoice for their upcoming rent payment. They have been renting from me for 6 months with zero issues and have never asked for this before, so I thought it was odd. I provided an invoice without asking questions because I like to be as "hands off" as possible. A few days later they informed me that I would be receiving rent from their employer via check (we usually collect rent through an online service although we are flexible). Should I be concerned? In what situation would this occur? Should/can I ask them details about the circumstances of this? They have been a great tenant so far and passed all of our screenings with flying colors so I would like to keep a good relationship.

Thanks!