I think stalls happen at random times and there's not a set schedule. We all have them and talk about them and it's true you just need to keep following the plan and the weight will come off, also measuring inches help too. I think our metabolism gets jacked, so mixing things up can help that (exercise, types of foods, amount of intake, etc).
I noticed that I'd stall everytime I worked out during that week and think I'm not getting enough calories or working out to hard. I'm in week 13 and have stalled (for a week) 2x now, but wasn't until later, I'll have a 0 loss week then a random 6lb loss.
Keep it up and as easy as it is to say but hard to do....don't get discouraged but I know it's frustrating!