Currently getActionPointsMax() function in actor.nut doesn’t return a floored value. This is an issue, when we modify the ActionPointMult to a decimal value e.g. 0.5 which will then return 4.5 for an actor with 9 action points. The max action points then show up as 4.5 in the UI as well. Please make the function return a floored value.
The this.Math.floor function in BB returns a float, so even after flooring this, it will remain a float and therefore not cause any problems with calculations.
EDIT: Just noticed that this has been fixed in vanilla (checked in version 1.5.0.12).