No Pellicle?

I've had a Flanders Red fermenting/aging in my basement for about 11 months now. With every sour I've done, I've ended up with a pellicle after about 5-6 months. With this beer, I only had a 5 gallon carboy available so I decided to use it. I've not seen a noticeable pellicle form with this beer.

Is this due to me using a smaller fermenter? The top layer of my beer isn't exposed to very much oxygen because it's filled all the way into the neck. Is this going to cause any issues? It tastes fine, but I've never seen a sour without a pellicle.

I didn't get a pellicle with my 1st Flanders Red, don't know why. I only let it go for about 7 months. It got mighty sour. My second batch is about 5 months old and I'm letting it go for a couple of years to see where it ends up.

No pellicle, no problem. The pellicle just means there is presence of O2.