Quadro M8L

I have a rule to get incoming call to two extensions and then start ringing to everyone if they dont answer. This works fine.

I just have one little problem that is getting annoying. Whenever someone try to call 3 extensions i have (100,101,102) 100 being one of my receptionnist, all the phone do a quick ring then stop. Even when i want to reach 101 from my internal phone all the phone ring one time... If i call another extension not in this list, the phone doesnt ring. I tried to find an option for that and didnt found anything.

I have incoming call setted up as :
Incoming call have welcome message -> transferred to 151 that is a many extensions ringing setted up to my two receptionnist (100 and 103) -> on wait timeout is goes ringing to 152 setted up as every phone in the company except the boss

I've checked all the parameters i have in these extensions with others working fine and its the same. Nothing particular too in the 151 and 152 virtual extension