I cannot confirm this, which is interesting in its own right.
For starters what channels are you watching? I'll clarify i am primarily watching "the main 50" from my phone (use both Apple and android)
I am just seeing the normal commercials as far as I can tell
But i believe you may be seeing the "middleware in action" - i somewhat recall reading jargon a while back implying they had the ability to work with distributors to easily pipe in their own advertisements. - kinda silly they'd advertise roku to roku users but that could just be a test run to roku signing its own deals and running other peoples ads in those spots