“No player in the first week of April saw the same map 5 times in a row in Competitive queue.
Now though, it seems that Riot has fixed this issue, as detailed in a recent dev post on the official website.
Given the efficiency of the system, it seems as though the system will remain the same for the foreseeable future.
Chung explained that Riot has replaced the system that governed map choices (based upon randomness) with one that deterministically minimizes map repeats for users without compromising on queue times.