Get ready for the next big net neutrality showdown, and this time, it’s all about video on mobile networks.

At the center of the most recent dispute about how network operators treat streaming services is Binge On, T-Mobile’s new mobile streaming initiative that exempts data from participating video providers from consumer’s monthly data allotments. T-Mobile announced the plan with big fanfare last month. To date, two dozen services have signed up to be part of Binge On, including Netflix, HBO Now and Hulu.

Google’s YouTube has been notably absent, but that hasn’t stopped T-Mobile from applying one particular aspect of Binge On to YouTube’s video streams: T-Mobile automatically throttles all video streams for users with Binge On, promising  “video streams at DVD quality” on its website. Binge On is automatically enabled for all users of qualifying data plans, but T-Mobile offers consumers a way to opt out of the program.

The operator presumably wants to lighten the data load on its networks by capping streaming rates at DVD quality levels, but it also applies the same rules to streams from other providers, including YouTube. This means that T-Mobile customers with Binge On enabled aren’t able to watch YouTube streams in HD, even though these streams count against their monthly data packages.

YouTube doesn’t think that’s fair. “Reducing data charges can be good for users, but it doesn’t justify throttling all video services, especially without explicit user consent,” a spokesperson told Variety via email Wednesday. T-Mobile didn’t immediately respond to a request for comment.

The Wall Street Journal first reported about the issue Tuesday.

The practice of exempting certain traffic from data plans and charges is known as zero-rating, and has been controversial in the past, with critics alleging that it violates net neutrality principles. The FCC hasn’t taken an official stance on T-Mobile’s Binge On, but the agency has started to look into the issue. Earlier this month, the FCC sent a letter to T-Mobile, asking for further review by next month.