PCGen not allowing improved trip at level 1 monk

I am trying to create a monk pc using PCGen however it is telling me I do not meet the requirements for Improved Trip. It says “MonkBonusFeatLVL at least 6”.

I am taking the Maneuver Master archetype which says I should be able to take any improved combat maneuver as a bonus feat.

I have 13 int and my other feats are Combat Reflexes and Vicious stomp (I am human)

Is this a bug with PCGen or am i missing something that means I am not allowed to take this feat?