Once again, both are ok depends on the situation. it's similar to the English word ''object'' (noun), object (verb). For example, if u say the noun basketball, it would be ''laam4''球, however, if u want to describe the state of the movement that u shoot the ball from your hand to the basket(射籃), then it becomes 射''laam2'' Another example, if u are carrying something with a basket(籃), in this case, both are ok but I personally would say ''laam2'' because it's more natural. A little tip for you, if I were you, I would just ignore this part in this stage because it's just overwhelming. it's just a minor accent problem. Widening your vocabulary, forming a correct sentence structure are the most important parts. U won't have any communication barrier as soon as u get these 2 parts done. The final step is to correct your accent a bit to go native. This is what I'm exactly doing in learning English.

lan 第二声 '乐案蓝 '这三个字连起来读就可以拼出来了。