@Anonymous User
It’s been within the last month or so. More so with the changes to Boost.
https://help.nowtv.com/article/we-are-making-some-changes
We're gradually rolling out ads in on-demand shows and movies (they're already on live channels). If you haven't seen any yet, you're likely to come across them from July, unless you've already got Boost.
Boost allows you to stream ad-free (excluding live channels and trailers promoting NOW content)
https://help.nowtv.com/article/can-i-watch-without-ads
https://help.nowtv.com/article/what-is-now-boost
FYI that I do not work for NOW, just a NOW customer trying to help