Hi Iso, I wanted to explain to you the issue you are seeing and what you can do to avoid it.
The "Keep Constructed Rank/MMR" option is a flag to tell the bot to concede the next non-arena/practice game it is playing. When enabled, and you win a game, the bot stores a value that tells it that it needs to concede the next game.
So, let's say you want to play games until 2 wins, and keep your stats approximately balanced (approximately, because the logic intentionally allows win creep due to multi-concede chains):
You start game 1
You win game 1: bot sets the flag so the next game played will be conceded.
You start game 2
Bot concedes game 2 because the flag is set and clears the flag.
You start game 3
You win game 3: bot sets the flag so the next game played will be conceded.
At this point, you have AutoStop set to to stop at 2 wins,
not at 2 concedes, so it actually stops. Please note, AutoStop is its own plugin, separate from the bot implementation that you run. HSB only has one bot implementation due to a number of unfortunate reasons, but if it had more, the design of things might make a little more sense because everything isn't tied together (which is why you can reset Stats, and it won't affect AutoStop, and vice-versa).
The next game you play, the bot
still has the flag set. That is because you had the bot stop before it finished balancing your stats. If we cleared the concede flag when you unchecked the option, then you'd see a heavily expedited process of win creep, because you're never conceding after your last game. The flag is global to "constructed", and not tied to individual game modes, because the config system is meant to be used to keep everything organized and separate. That's not to say it might not be better for more logic to try and keep track of which game mode you are in, but these plugins and implementations are simple and work, so it might be a future consideration.
Obviously though, this isn't desired in your case due to the loss of rank as you mentioned, so here's some tips as to how you can avoid it.
First, consider making different configs for your different game modes. The initial config is called Default, but if you use it to do a bunch of different things, you'll run into settings conflicts like this. Instead, at startup, type a new name instead of Default, and all your settings will be kept specific to that config. Only use that config for the game modes/decks you have it set to, and you should avoid most issues.
Second, if you don't want to make different configs, I highly recommend you do though, you need to set AutoStop to stop based on Concedes. One thing that isn't made super clear (because the option has existed long before the AI did it) is that the concede tracking is "win-concede tracking", not the AI conceding in a losing situation. If you were to stop at 2 concedes instead of 2 wins, your stats would be balanced, so when AutoStop actually kicked in, the next game you play will not be a concede.
Give either of those a try and see if you can find which works best for you, good luck!
