I am a Permanent Resident in Canada. Have been here since July 2014. I got a 10 year B2 visa in August 2015 (I am currently working full time). In Sept 2015, I went to the states for a wedding - came back to Canada within a week for work but the stamp on the passport showed i could have stayed until May 2016. If I am heading back to the States for a week this December will this be a problem? The gap between my first and my upcoming second visit is a month.
There is no waiting period. You must (as always) simply be able to demonstrate to the CBP officer that you are not trying to live or work in the United States. Bringing your Canadian permanent resident card and some documents about your employment would be helpful to this end.