No. The oil is for better mouthfeel because LC breads can be fairly dry. The big bubble sounds like it could be technical - either there was an air bubble trapped inside the dough, or some of the yeast may not have been thoroughly dissolved. You usually only see big holes in slowly developed traditional doughs that use a starter. I've only dabbled in LC bread and have found that they have a very tight crumb. Not airy at all.

Practice makes perfect!

Karen