Role Queue Beta which runs from August 13th to August 31st will NOT count to your long-term Competitive Hidden Matchmaking Rating when it comes time to determine your MMR for Season 18. Both Role Queue Beta and Season 18 (starting September 1st will take into account data collected over the last six months to determine everyone’s role specific MMR when they play their starting placement matches.
ATTENTION: This has been corrected by the development team here: