RPGMAKER MV "TYPEERROR - UNDEFINED IS NOT A FUNCTION"

When using YEP BattleEngineCore plugin on RM MV I get this error message after the first turn has passed in battle with the playable characters and the enemies having finished their moves.

Here's what F8 brings up:

"TypeError: undefined is not a function
at Game_Troop.Game_Unit.refreshMembers
at Function.BattleManager.refreshAllMembers
at Function.BattleManager.endTurn
at Function.BattleManager.updateTurn
at Function.BattleManager.update
at Scene_Battle.updateBattleProcess
at Scene_Battle.update
at Scence_Battle.update
at Function.SceneManager.updateScene
at Function.SceneManager.updateMain"

The error occurs even if I don't tinker with any of the plugin settings. Really troublesome :/ I'd be really grateful if someone would come up with a solution.

Here are the lines:


I got few other scripts/plugins running, but they shouldn't interrupt with the Battle Engine. I got one for lighting effects and another for main menu portraits.

author=LockeZ
Well, something's definitely set up wrong.

I know it says the error is happening in the BattleEngineCore plugin, but check and make sure that the game works if you disable the BattleEngineCore plugin and leave everything else how it is right now.

Everything works just fine if I disable BattleEngineCore. I tried disabling all the other plugins and only left BattleEngineCore running, but it still crashes. I also tried creating a completely new project with only this BattleEngineCore running and still it's crashing........