T-Mobile and its chief executive John Legere love bashing rival wireless carriers for a wide range of reasons. Among them, of course, has been the lack of truly unlimited data at Verizon Wireless and AT&T. Both of the nation’s top wireless carriers still offer unlimited data to subscribers with grandfathered plans, but they slow data speeds after a certain threshold has been reached — a practise called throttling. Now, it looks like T-Mobile is getting ready to do a bit of backtracking as it prepares to begin throttling its “truly unlimited” data plans for some users.

In a supposed internal memo obtained by the often-reliable blog TmoNews, T-Mobile stated that it will soon start throttling unlimited data plan users who use their devices for peer-to-peer file-sharing or to download torrents.

“T-mobile has identified customers who are heavy data users and are engaged in peer-to-peer file sharing, and tethering outside of T-Mobile’s Terms and Conditions (T&C). This results in a negative data network experience for T-Mobile customers,” T-Mobile said in the internal memo. “Beginning August 17, T-Mobile will begin to address customers who are conducting activities outside of T-Mobile’s T&Cs.”

The carrier’s logic is certainly understandable, but it will be interesting to see if T-Mobile and its CEO continue to make claims about truly unlimited data plans after they begin throttling torrent users.

An image of the leaked memo follows below.

UPDATE: T-Mobile says it will not throttle any users, but will instead contact subscribers who are in violation of the company’s terms. “We are planning to reach out them and let them know and help them change,” T-Mobile CMO Mike Sievert told Re/code.