I don't have any insider knowledge to how Battalion is working their Elo Ranked system but i do have a very good grasp of Elo in general.
I have seen multiple people with this same issue and this is in my opinion why we are seeing it;
In most games where they do "Calibration Matches" the K factor (the numbered amount you will increase / decrease if both teams are equal in laymen terms) will be large. Allowing for growth and dips fairly quickly with limited matches. This is used to "roughly" gauge the players skill area and quite often games will take into account your impact in the game (which is usually toned down after wards in normal ranked matches).
In this game i feel as if they haven't. Now for example let's say in this game Bronze 1 to Diamond 5 is an Elo of 1-5000. It looks like this game has set every one at around 500-1000 for Calibration and then just started a "normal matchmaking process". This means even after going 9-1, 10-0 etc the max you will get is Silver 3 due to no one being higher to give you an "Elo boost" after a win. The K factor is staying stagnate around "25".
Now that you have Calibrated in the top 5% of Silver 3 (guessing btw just for arguments sake) there is no matches that is given you more than 25 Elo even after a win and thus will increase incredibly slowly compared to other Elo based match making games.
Could be wrong but this is my take on it.