Okay, so I installed a new project, it didn't work, then I installed a few other plugins (namely YEP stuff) and it suddenly started working, and then after testing and installing a few more scripts it suddenly bricked again. Disabling all scripts again did not fix it...There must be something really wrong!
So, I need help understanding this! This plugin works perfectly with or without other plugins on my current game project (the in-engine playtesting). But I have built my game project and sent it to my playtester, and all sorts of wrong things happen! He sent me the test files, and I saw many things wrong. I have also started a new project, and the plugin doesn't work well, like on your project, even in the in-engine playtesting.
I've found out what the problem is! It's in the settings, and it isn't a bug. Suppose you have set the first parameter of the plugin to "false" and the second parameter to the number of battlers there are. In that case, it won't add a turn if you try to because you have set the maximum amount of turns there, and the amount of battlers is equal to or greater than that amount as every turn you start with as many turns as there are friendly battlers.
Edit: You can increase that second plugin parameter to include new max turns if you want more turns than the number of battlers. Or you can set the first plugin parameter to "true" and make the maximum number of turns based on the number of alive battlers at the start of the turn. You can set the maximum number of turns per battler in the third parameter.
