I have an L-1 Blanket petition and I traveled to US for one week and used that VISA. Part of my job, I need to work in one of our offices outside USA for a year, but will just have to go to US for one week every 2 months. Will that affect my visa since I would not be fulltime working in US? I have M entries in my L-1.
As long as you work full time and on the job described in your L-1B while you are INSIDE USA, it does not matter how long you stay outside USA.